Guides (don't use)

NexGate — Commerce, Location & Logistics Master Guide

Purpose. This is the single reference for how buying, location and shipping work in NexGate. It captures every decision made so far and the reasoning behind each one, so that any implementer (human or Claude Code) can build from it, and future-you remembers why.

Companion file: location-service-spec.md is the detailed build spec for the Location Service. This guide is the wider picture; that spec is the first thing to build.

Guiding rule for everything here: simple over clever. No approval workflows, no features nobody asked for, no machinery a solo developer can't maintain. Where a simpler rule does the job, it wins.

0. The idea in one picture

NexGate is a social-commerce super app: users open shops to sell and delivery businesses to ship, and buyers order and get goods delivered or collect them. NexGate never owns stock or vehicles — it connects the three sides and holds the money safely in between.

            ┌──────────────┐     browse / order / pay      ┌──────────────┐
            │    BUYER     │ ───────────────────────────►  │   NexGate    │
            └──────────────┘ ◄───────────────────────────  │  (platform)  │
                   ▲   collect / receive + confirm (code)   │   + escrow   │
                   │                                        └──────┬───────┘
                   │                                   recommends & books
                   │                                               │
         ┌─────────┴─────────┐                        ┌────────────┴───────────┐
         │   SHOP (seller)   │  hand over + code      │  DELIVERY BUSINESS     │
         │  items, location  │ ─────────────────────► │  (shipper) moves goods │
         └───────────────────┘                        └────────────────────────┘

  Money path:  Buyer → escrow → (on delivery code) → seller wallet + shipper wallet + NexGate fee

Everything in this guide hangs off two services:

  1. Location Service — where things are. The foundation. Built first.
  2. Shipping Service — how goods move. Built on top of Location.

1. Core principles (apply everywhere)

  1. The pin (lat/lng) is the single source of truth for any place. Text is only a label.
  2. Location is collected only for a stated reason, never on app open, never as background tracking.
  3. The administrative hierarchy (region/district/ward) comes from NexGate's own data, computed from official NBS ward boundaries. Google is used only on the client for the map, place search and the live label — never called from the backend, never stored.
  4. Orders freeze a copy of every address and price. Later edits never change a past order.
  5. Users own businesses; businesses earn into the owner's one wallet. Shops sell, delivery businesses ship. Same ownership model for both.
  6. Money is held in escrow and released on a delivery code. Proof of handover, not trust.
  7. One shipment = one pickup (one shop) → one shipper → one drop-off. No multi-stop.
  8. Accept orders 24/7; be honest about timing. Closed hours delay the work, never the sale.
  9. Shippers describe their own pricing and coverage. NexGate never forces a pricing model.
  10. Trust is automatic, not a manual queue — phone verify, limits that grow with good history, ratings, and auto-pause on repeated failure.

2. Location Service (foundation)

Full build detail is in location-service-spec.md. This is the summary.

2.1 What it owns

2.2 How a pin becomes a place

          📍 confirmed pin (lat, lng)
         /                           \
  NBS ward shapes (ours)          Google (client only)
  region, district, ward, codes    "Mlimani City, Sinza Mori…"
       │                                │
    STORED (truth)              shown while placing the pin only
                                (never sent to backend, never stored)

The lookup is a point-in-polygon test in PostGIS: which ward shape contains this point? It runs in milliseconds thanks to a spatial (GIST) index. If no ward contains the pin (beaches, lakes, borders), fall back to the nearest ward within 500 m; beyond that, the pin is "outside coverage".

2.3 The ward data (done)

District and region need no separate data. Every ward row already carries its council, district and region names + codes, so one pin lookup returns all levels at once. Coverage checks and reports just use the stored codes. The only case needing a district/region shape is drawing an outline on a map — build it on demand by dissolving wards (ST_Union(geom) GROUP BY reg_code[, dist_code]), never store a second dataset.

2.4 Address capture UX (same pin screen everywhere)

3. Shipping Service (built on Location)

3.1 The whole shipping picture

                          ┌───────────────────────────────┐
                          │   RECOMMENDATION ENGINE        │
   order (items, value,   │   1. read situation            │   ranked options:
   pickup+dropoff wards,  │   2. gather eligible shippers  │   💰 Cheapest
   bulky?) ──────────────►│   3. filter (coverage/limits)  │──►⚡ Fastest
                          │   4. price each                │   ⭐ Recommended
                          │   5. rank & label              │
                          └───────────────┬────────────────┘
                                          │ one standard contract per shipper:
                                          │ covers? · quote · book · cancel · status
                     ┌────────────────────┼─────────────────────┐
                     ▼                                          ▼
          ┌───────────────────┐                     ┌───────────────────────┐
          │ NATIVE shipper    │                     │ INTEGRATED shipper    │
          │ (NexGate business)│                     │ (external API)        │
          │ tables + app/SMS  │                     │ Bolt, DHL… adapters   │
          └───────────────────┘                     └───────────────────────┘

3.2 Two classifications of every shipper

A shipper is described by two independent fields:

A. Service type — how goods move

Type How it works Coverage set by Examples
🚪 Door-to-door Picks up at seller, delivers to buyer Areas (ward/district/region, or nationwide) + optional max distance Boda groups, Kibuti Express, DHL / EMS (wide area)
🚌 Station Seller drops at a station, buyer collects at a station Stations (pins) + lanes between them Bus companies, truck offices

"Local" vs "intercity" is not a separate type — it falls out of how wide the area is. DHL is just door-to-door with a nationwide area.

B. Connection — how NexGate talks to them

Native (NexGate business) Integrated (external API)
Set up by The owner, in the app NexGate, once, in code + admin
Pricing Owner's tables Live from their API
Jobs arrive App notification + SMS/WhatsApp link NexGate calls their API
Status Owner taps buttons / link Their webhooks or polling → mapped
Money Into owner's NexGate wallet NexGate pays them; they invoice NexGate
New one Zero code (user signs up) One adapter per company

They combine freely: a native door-to-door rider, a native station bus, integrated Bolt, integrated DHL.

3.3 One standard contract (why the engine never changes)

Every shipper, native or integrated, answers the same five questions. That's all the engine knows:

boolean covers(pickupWard, dropoffWard);     // area / lane check
Quote   quote(order);                         // price + ETA
Booking book(order);                          // returns a reference
void    cancel(ref);
Status  status(ref);                          // mapped to NexGate statuses

Standard status ladder (every provider's own statuses are translated into this, so the buyer's tracking screen never changes):

CREATED → BOOKED → PICKED_UP → IN_TRANSIT → AT_STATION → OUT_FOR_DELIVERY → DELIVERED
                                                   ↘ FAILED / CANCELLED / RETURNED

3.4 Adding a provider = data, not code (for native)

┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐
  Add delivery business
┆ Name:    Shabiby Bus Parcels          ┆
  Type:    ○ Door-to-door  ● Station
┆ Connect: ● Native  ○ Integrated (API) ┆
  Contact: +255 7XX…  (booking line)
┆ ───────────────────────────────────── ┆
  Coverage
┆  Door-to-door → pick areas            ┆
   Station      → add stations + lanes
┆ Pricing method (§3.6)                 ┆
  Limits: max distance / max value
┆ Bulky:  ○ No  ● Yes (+extra)          ┆
  Settlement: ● Wallet  ○ Pay at station
┆ [ ] Enabled                           ┆
└ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘

Integrated providers (Bolt, DHL) enter nothing here; their adapter handles it.

3.5 Coverage: picked from what the system already knows

Door-to-door → areas (from the region → district → ward list, or nationwide):

Mbeya Riders   🚪  area: Mbeya district        → local only
Kibuti Express 🚪  area: Dar + Pwani           → regional
DHL / EMS      🚪  area: nationwide            → intercity door-to-door

Offered only when both pickup and drop-off pins fall inside its area.

Station → stations + lanes (each station is a pin resolved to a ward, like a shop):

Shabiby Bus 🚌
  Stations: Mbeya Stand · Magufuli Terminal (Dar) · Dodoma Terminal
  Lanes:    Mbeya ↔ Dar   · Mbeya ↔ Dodoma

Offered when it has a station near pickup and near drop-off. Buyer sees nearest stations first. Optionally a station shipper also delivers to the door around a station (then it also picks areas).

Routes with multiple stops on the way. A bus line usually stops at several towns in order (Mbeya → Iringa → Morogoro → Dar). The shipper enters one route = an ordered list of its stations, not every pair of lanes. The system then treats any earlier stop → any later stop on that route as a valid trip (both directions if the route runs both ways):

Route "Mbeya–Dar daily"  (both ways)
  1. Mbeya Stand   2. Iringa Office   3. Morogoro Stand   4. Magufuli (Dar)
  → valid trips: Mbeya→Iringa, Mbeya→Morogoro, Mbeya→Dar,
                 Iringa→Morogoro, Iringa→Dar, Morogoro→Dar (+ reverses)

4 stops → all pairs auto-derived. Add a 5th stop and its new pairs appear at once.

Pricing along a route (shipper's choice):

Plus the usual value add-on (insurance) and bulky extra. First/last mile to a buyer not near a stop is added as a separate local door-to-door leg, each with its own code — unchanged.

A lane is just the special case of a route with two stops. Model everything as routes.

3.6 Pricing — the shipper chooses the model, NexGate never forces one

At registration the shipper picks one method:

How do you charge?
 ○ Flat price
 ○ By distance            (bands: 0–3 km, 3–7 km, …)
 ○ By package value       (ladder: insurance — the shipper carries the risk)
 ○ By distance + value    (added together)
 ○ Combined table         (distance × value grid, each cell a full price)

Plus, on top: bulky extra (if accepted), max distance and max value (filters, only when set).

Why value-based for parcels: the shipper holds the insurance, so charging by the goods' value is fair, and "max accepted value" caps their risk. Quantity is handled for free — more items means a higher order value.

Distance is measured from the two pins: start with straight-line × 1.3 (free, instant), switch to a routing service later if needed without changing shipper tables.

Examples (5 km trip, phone worth 800,000):
  Mbeya Riders     distance only      3,500
  Shabiby (lane)   value only        20,000
  Kariakoo courier distance + value   3,500 + 3,000 = 6,500
  Combined table   (3–7km × 500k–2M)             7,000
  Small rider      flat               3,000

3.7 Package info — minimal

No size or weight. Only:

Vehicle type is not needed — "bulky vs not" is the only decision it would inform. Shippers may add a vehicle badge for display only (e.g. "Boda", "Pickup"); it drives no logic. Integrated providers (Bolt) pick the vehicle category inside their adapter.

Mismatch rule: if the real package differs (bulky not ticked), the extra cost is the seller's (they chose), the buyer's price never changes after payment, and repeated mismatches auto-correct the product's bulky flag.

3.8 Who enters what

Party At setup (once) Per order
Seller Shop location, landmark, phone [ ] Bulky (usually none); tap "Ready for pickup"
Shipper Coverage + one pricing method + limits + bulky Tap link; update status
Buyer — Pick a delivery pin; tap one option (Cheapest/Fastest/Recommended)

The system works out the rest: value, bulky, pickup+drop-off wards, eligible shippers, price, ranking.

3.9 The recommendation engine, step by step

1. WHERE   pickup ward + drop-off ward → same district / same region / different region
2. WHO     shippers whose coverage (areas / lanes) includes both wards
           + build station + door-to-door combinations where needed
3. FILTER  drop any that fail a hard rule:
             area/lane not covered · over max distance · over max value
             · bulky needed but not accepted · closed & past cut-off (→ ETA shifts, not dropped)
             · provider currently auto-paused (repeated failures)
4. PRICE   live quote (integrated) or the shipper's table (native)
5. RANK    score by price · speed · reliability(history); weight by situation
           (urgent → speed; cheap item → price; expensive → reliability)
           label 💰 Cheapest / ⚡ Fastest / ⭐ Recommended; drop absurd outliers

Backup: if the chosen shipper fails (no pickup, cancels), auto-offer the next best and tell the buyer.

Reliability needs history, so at launch show only Cheapest and Fastest; add Recommended once real delivery data exists. Reliability is your long-term moat — competitors can copy features, not your data.

3.10 Shipper onboarding: register → KYC → go live

Shippers handle other people's goods and money, so onboarding has three parts. KYC gates going live, not filling the form — let them build the profile, then verify to switch on. Trust then grows automatically; no manual approval queue except on a flagged exception.

Register (6-step form) → KYC verify → GO LIVE (low limit) → limits & badge grow with history

Registration form (a short wizard, save-as-draft, admin can fill it for offline shippers):

Step Fields Feeds the engine as
1 Basics name · service type (DOOR/STATION) · booking phone · WhatsApp? · logo identity, notify, branches next step
2 Coverage DOOR: areas (region/district/ward) or radius-from-base · STATION: stations + routes coverage check
3 Pricing method (flat/distance/value/dist+value/grid; route segment or table) · bulky yes/no (+extra) quote
4 Limits & alerts max value · max distance · won't-carry list · response window (default 30 min) · advance heads-up (default ON) filters, job alerts (§4.3a)
5 Hours & money opening hours + cut-off · settlement (wallet / pay-at-station) · payout account ETA/availability, money routing
6 Verify phone OTP · agree shipper terms (liability up to declared value) go live

Minimum to go live = steps 1–3; steps 4–5 have working defaults; step 6 is just verify. A one-man rider finishes in ~2 min; a bus company takes longer only because it adds stations.

KYC — fast, tiered, mostly automatic:

Tier 0  phone verified            → register, build profile (not live)
Tier 1  + NIDA + ID photo + selfie match  → GO LIVE, low max value (e.g. 200,000/order)
Tier 2  + payout name matches NIDA → higher limit
Tier 3  good history (N jobs, rating, low failures) → higher limit + "Verified" badge

Licences & compliance — collect now, confirm mandatory ones with a professional later. Store each as document type + file + expiry. Mark required/optional per shipper type & tier once advised. Non-blocking at launch; uploading the real ones earns a "Verified business" badge.

Group Documents (collect if the shipper has them)
Identity & business NIDA · TIN (TRA) · BRELA (business name / company) · local-govt business licence · VAT (VRN) if over threshold
Transport / courier LATRA licence (road carriage of goods/passengers — replaced SUMATRA) · TCRA courier/postal licence (door-to-door couriers) · TASAC (if freight-forwarding)
Vehicle & driver (own fleet) vehicle registration · commercial/PSV licence · motor insurance (+ goods-in-transit) · driving licence · inspection/fitness
Employees (if any) NSSF · WCF · OSHA
Money / insurance mobile-money/bank payout · goods-in-transit / cargo insurance

4. Order & money flow

4.1 Checkout — pickup or delivery, per shop

Each shop in the cart is its own shipment, so the choice is per shop:

┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐
  Deliver to: 🏠 Home, Mbezi Juu
┆ 🏪 Shop A · Kariakoo · 2 items        ┆
   ○ Pickup at shop            Free
┆  ● Delivery 🚪 Kibuti Express 4,000 ▾ ┆
  🏪 Shop B · Sinza · 1 item
┆  ● Pickup at shop            Free     ┆
   ○ Delivery
┆ 🏪 Shop C · Mbeya · 1 item            ┆
   ● Delivery 🚌 Shabiby       20,000 ▾
┆ ─────────────────────────────────────┆
  Delivery total (2 deliveries) 24,000
└ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘

4.2 Escrow + delivery codes (proof of handover)

sequenceDiagram
    actor Buyer
    participant NexGate as NexGate (escrow)
    participant Seller
    participant Shipper
    Buyer->>NexGate: pay (item + delivery)
    Note over NexGate: funds held in escrow
    Seller->>Shipper: hand over + SELLER pickup code
    Shipper->>NexGate: enter pickup code (proves shipper has it)
    Shipper->>Buyer: deliver
    Buyer->>Shipper: give DELIVERY code
    Shipper->>NexGate: enter delivery code
    Note over NexGate: release:
    NexGate->>Seller: item price − commission
    NexGate->>Shipper: delivery fee − commission
    NexGate->>NexGate: commissions

Code rules (decided):

Open decisions to finalise (see §8): buyer unreachable / forgets code; item wrong or damaged after code; return window; cancellation cost.

4.3 Switching pickup ↔ delivery after ordering

Order placed as PICKUP → "Get it delivered instead"
   → pick drop-off pin → fresh delivery quotes (today's prices)
   → pay delivery fee only → into escrow → shipment created, seller notified
   Allowed until the buyer has collected.

Order placed as DELIVERY → "Collect it myself"
   → allowed only BEFORE the shipper has picked it up
   → delivery fee refunded to the buyer

4.3a When the shipper is contacted — offer at "Ready", not before

The seller has two separate actions, and the shipper is only offered the job at the second one:

Order arrives → seller ACCEPTS (yes, I'll fulfil)   ← shipper NOT contacted yet
             → seller PACKS
             → seller taps READY FOR PICKUP          ← NOW the binding offer goes to the shipper

Offering at Ready (not at Accept) means: no shipper rides over to wait while the shop packs; if the seller can't fulfil, the order dies before any shipper was bothered; and the ETA/response-window start from a real ready moment.

Heads-up (optional, per-shipper setting — default ON, can be disabled). So shippers can plan without being booked early, NexGate sends a non-binding heads-up when the seller accepts/starts packing. It commits nothing and starts no timer:

On seller accept/pack →  Heads-up (no commitment):  "Order coming from Sinza, ~15 min. Be ready?"
On seller READY       →  Binding OFFER + response window (30 min) starts   ← the one that counts

4.4 Shipper rejects the job → auto-reassign

A shipper can decline an offered shipment (too far, too busy, bulky they can't carry, value too high, closed). This must resolve cleanly, because it touches money. Two rules make it safe:

  1. Escrow holds two parts — item money and delivery money. A rejection only touches the delivery part. The item money stays held, and the seller never re-approves — their job ended at "ready".
  2. The buyer's agreed price is protected. The system can reassign silently only if it holds that price or beats it; a higher price needs the buyer's yes.

The flow:

Seller taps READY (§4.3a) → shipment OFFERED to chosen shipper (delivery fee held)
   → shipper has a response window (e.g. 30 min, or until they next open)
        ├─ ACCEPT          → pickup (code) → normal flow
        └─ REJECT (reason) or TIMEOUT
              → that shipper's delivery fee released back in escrow
              → shipment = REASSIGNING, recompute options excluding rejecters

flowchart TD
    A[Shipper rejects / times out] --> B{Next-best shipper?}
    B -- none --> C[Buyer: switch to pickup refund, or cancel full refund]
    B -- same price or cheaper --> D[Auto-book next · refund difference to wallet]
    D --> E[Notify buyer: new courier, same price · NO action needed]
    B -- costs more --> F[Delivery money to buyer wallet · show fresh options+prices]
    F --> G[Buyer picks one · pays difference from wallet]
    G --> H[New shipper acts]
    E --> H

There is no repeated approval — the seller is out of it after "ready", and the buyer is pulled in only when the price would rise or nobody is left. Otherwise the system does the chasing.

5. Free shipping

Two funders, same mechanism. The shipper is always paid in full; the discount is covered by whoever offered it, deducted at escrow release.

5.1 Seller-funded (per shop or per product)

┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐
  Free delivery (shop setting)
┆ [✓] Offer free delivery              ┆
  Where:  ○ Within [5] km of shop
┆         ● Areas: Ubungo, Kinondoni   ┆
  When:   order over [50,000] (opt.)
┆ I pay up to: [5,000] per delivery    ┆
└ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘
Product override:  ● Use shop setting  ○ Always free  ○ Never free

Uses your ward boundaries and pin distance to decide eligibility. The cheapest qualifying option becomes free; a faster choice costs the difference. The cap protects the seller (buyer pays the rest above it). In a mixed shipment, free only if every item qualifies.

5.2 NexGate-funded (campaigns)

┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐
  Campaign: Free delivery Dar weekend
┆ Areas: Dar es Salaam · Dates: 10–12 Oct
  Min order: 30,000 · NexGate pays up to 3,000
┆ Who: First order only · Shops: All    ┆
  Total budget: 2,000,000 → auto-stops
└ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘

Stacking (seller first, then NexGate):

delivery price            7,000
− seller pays (cap 4,000) −4,000
− NexGate pays (cap 3,000) −3,000
= buyer pays                  0

A total budget auto-stops the campaign — no runaway cost. Each shipment records who paid what.

6. Opening hours & orders outside hours

6.1 Hours apply to three things

Who Why
Shops Pickup availability; when a shipper can collect
Delivery businesses Offered as "today" only when working; else ETA shifts
Stations Where buyers collect parcels (often different hours from the company)

6.2 Hours editor (same screen everywhere)

Mon–Fri  08:00–13:00 · 14:00–18:00      ← several ranges per day (lunch break)
Sat      09:00–15:00
Sun      Closed
Special days: 25 Dec Closed · 9 Dec 10:00–14:00   ← override weekly (holidays, Eid)
[ ] Temporarily closed (one-tap pause)
Same-day cut-off: 16:00 (shippers)       ← after this, pickup = next opening

All times EAT (UTC+3). Overnight ranges (18:00–02:00) allowed.

6.3 Orders outside hours — accept 24/7, be honest

Order at Fri 22:00, shop opens Sat 09:00
  ○ Pickup   → "Ready from Sat 09:00"
  ● Delivery → "Arrives Sat ~12:00–15:00"

Rules:

7. What we learned from others (and what to copy / avoid)

Topic Jumia / Glovo / Uber / Bolt do… NexGate decision
Ordering when closed Pre-order / scheduled ✅ Accept 24/7, show real time
Delivery choice Door vs pickup station, options with price+ETA ✅ Per shop, Cheapest/Fastest/Recommended
Money safety Escrow + 4-digit code ✅ Have it
Seller onboarding Heavy docs + approval queue ❌ Avoid — phone verify + auto-limits
Surge pricing Uber/Bolt dynamic ❌ Avoid — shipper ladders are clearer
Separate rider apps Yes ❌ Avoid — NexGate deals with the business, not riders

To add from others (currently gaps):

  1. Problem-report window — buyer can report a problem within ~24h of delivery before escrow releases.
  2. Two-way ratings — rate the buyer too (bad address / no-show), so shippers aren't stuck with them.
  3. Cancellation policy with cost — who pays when a buyer cancels after the shipper collected.
  4. Late-handover consequence — feed seller late handovers into the same reliability score shippers have.
  5. Address quality nudges — already helped by pin + landmark + ward check.

8. Open decisions to finalise before building Shipping

# Decision Suggested default
1 Buyer unreachable / forgets delivery code Shipper marks "Delivered, no code" + photo → buyer 48h to dispute → else auto-release
2 Item wrong/damaged after code Short report window (24h) before release, or code = final
3 Lost / damaged parcel Shipper liable up to declared value; refund from shipper wallet; pickup code shows who held it
4 Cash on delivery (COD) Prepaid only at launch; add "accepts COD" per shipper later
5 Escrow legality Check with a lawyer / payment partner (BoT, National Payment Systems Act) — not legal advice
6 Cancellation cost Free before pickup; buyer bears shipper's cost after pickup
7 Bolt for parcels RESOLVED (confirmed with Bolt): no parcel/delivery API in Tanzania — passenger rides only. Bolt is out as a shipper; rely on native shippers. Bolt only relevant if NexGate later adds an in-app passenger-ride feature (separate from shipping).
8 Mandatory licences & platform liability Which of LATRA / TCRA / business licence etc. are required per shipper type, and NexGate's liability as connector — confirm with a Tanzanian lawyer / compliance pro (§3.10)
9 KYC / AML level How much identity NexGate must verify & keep for shippers and sellers holding escrowed money — confirm with payment partner / lawyer

9. Note on the Bolt Ride Booker API (reference)

Confirmed with Bolt (Oct 2026): no parcel/delivery API in Tanzania — passenger rides only. So Bolt is not a NexGate shipper. This section is kept only for a possible future in-app passenger-ride feature (separate from shipping). Prime Stack already has a Bolt Business account (ride billing), which is not the same as Ride Booker API access.

The API doc shared earlier is a reseller passenger-ride API, useful as a model for integrated providers but not a parcel API. Key facts if it's ever used (e.g. in-app rides):

For NexGate's parcel shipping, native shippers matter far more than Bolt. Treat any Bolt/DHL integration as one adapter behind the standard contract (§3.3).

10. Build order (roadmap)

Phase 1 — Location Service  ◄── START HERE (spec + data ready)
  Docker PostGIS · seeder · pin resolution · shop location · buyer addresses · snapshots

Phase 2 — Native Door-to-door shipping, one city
  Delivery business type · coverage (areas) · one pricing method · bulky flag
  Escrow + pickup & delivery codes · prepaid only · status via app/SMS link
  Checkout: pickup/delivery per shop · Cheapest + Fastest only

Phase 3 — Station shipping (intercity)
  Stations + lanes · multi-leg codes · collect-at-station

Phase 4 — Recommendation engine grows
  Reliability scores from history → add "Recommended"
  Free shipping (seller + NexGate campaigns) · opening-hours scheduling

Phase 5 — Integrated providers
  Integrated adapters behind the standard contract — e.g. DHL (confirm parcel APIs first).
  NOT Bolt: confirmed no parcel API in TZ (rides only).

Cross-cutting (fold in as you go): two-way ratings, problem-report window,
cancellation policy, late-handover scoring.

Do first: sign up your own first shippers (a few boda groups + one bus company) in one city — recommendations are worthless with no shippers.

11. Data model sketch (shipping — for when you build it)

Logical only. Follow the project's ID type, audit and error conventions. All areas/stations point to the ward / district / region codes from the Location Service — no new map data needed.

delivery_businesses   owner_user_id, name, service_type(DOOR|STATION),
                      connection(NATIVE|INTEGRATED), adapter_name?, contact_phone,
                      accepts_bulky, bulky_extra, max_distance?, max_value?,
                      response_window_min(default 30), advance_headsup(default true),
                      settlement(WALLET|PAY_AT_STATION), enabled, rating, reliability

business_areas        business_id → region/district/ward codes it serves   (DOOR)
business_stations     business_id, name, pin(lat,lng), ward_id, phone, hours (STATION)
business_routes       business_id, name, both_ways                          (STATION)
route_stops           route_id, station_id, stop_order                      (ordered list)
                      → valid trip = earlier stop_order → later stop_order on same route
                        (a 2-stop route is just a "lane")
pricing_rules         business_id, method(FLAT|DISTANCE|VALUE|DIST_VALUE|GRID),
                      bands/ladder/grid as JSON
route_pricing         route_id, mode(SEGMENT|TABLE),
                      segment prices between neighbours, or stop-to-stop table (STATION)

opening_hours         owner_type(SHOP|BUSINESS|STATION), owner_id,
                      weekly ranges, special_days, temp_closed, same_day_cutoff

shipments             order_id, shop_id, shipper_business_id, service_type,
                      pickup_snapshot, dropoff_snapshot (frozen),
                      price, who_pays(buyer/seller/nexgate split),
                      status(OFFERED|ACCEPTED|REASSIGNING|PICKED_UP|IN_TRANSIT|
                             AT_STATION|OUT_FOR_DELIVERY|DELIVERED|FAILED|CANCELLED),
                      offer_expires_at, reassign_count,
                      pickup_code, delivery_code, leg_no?
shipment_offers       shipment_id, business_id, state(OFFERED|ACCEPTED|REJECTED|TIMEOUT),
                      reject_reason?, offered_at, responded_at   (one row per attempt)
shipment_legs         shipment_id, from, to, provider, status, cost, code   (multi-leg)

escrow_holds          order_id, item_amount, delivery_amount,
                      state(HELD|RELEASED|REFUNDED), breakdown   (two parts: item + delivery)
campaigns             areas, dates, min_order, cap_per_delivery, budget, audience, active

12. Worked examples (engine walk-throughs)

Illustrative numbers only. Shows the 5-step engine (WHERE · WHO · FILTER · PRICE · RANK) end to end. Reminder of the rules: value → price + insurance, bulky → vehicle/who can carry, quantity flows into value by itself, hours & limits filter, area/route decides eligibility.

The registered shippers (set up once — used by all examples)

① Mbezi Boda        🚪 DOOR · Native
   Areas: Kinondoni, Ubungo (Dar)      Pricing: distance
     0–3km 2,000 · 3–7km 3,500 · 7–15km 5,000 · max 15km
   Bulky: NO        Hours: 07:00–20:00

② Dar Cargo         🚪 DOOR · Native
   Areas: whole Dar es Salaam region   Pricing: distance + value
     dist: 0–5km 4,000 · 5–15km 7,000   value add: >500k +2,000
   Bulky: YES (+15,000, car)           Hours: 08:00–18:00

③ Shabiby Parcels   🚌 STATION · Native
   Route: Mbeya–Dar (both ways): Mbeya ▸ Iringa ▸ Morogoro ▸ Dar
     segment: Mbeya–Iringa 8k · Iringa–Moro 6k · Moro–Dar 7k
   value add: >1M +5,000 · Bulky: YES (+10,000)  Hours: 06:00–19:00

④ EMS Courier       🚪 DOOR · Native · nationwide
   Pricing: value ladder   ≤200k 15k · ≤1M 25k · >1M 3%
   Bulky: YES (+5,000)     Hours: 08:00–16:00 Mon–Fri

A — small but many, same city

20 phone cases, Sinza (Ubungo) → Mbezi (Kinondoni). Value 120,000, not bulky, ~6 km, Sun 14:00.

1 WHERE   both in Dar region, ~6 km
2 WHO     ① ✓  ② ✓  ③ ✗ (no Dar-local)  ④ ✓
3 FILTER  value ok · not bulky · ④ CLOSED Sun ✗   → candidates ① ②
4 PRICE   ① 6km = 3,500      ② 7,000 + value add 0 = 7,000
5 RANK    💰⚡ ① Mbezi Boda 3,500 ~40min · alt ② 7,000

Buyer sees: 🚪 Mbezi Boda — 3,500 · ~40 min. Quantity raised value, but it still fits a bike.

B — one but large (bulky, cheap)

1 mattress, same shops. Value 85,000, Bulky ticked, ~6 km, Sun 14:00.

2 WHO     ① ② ④ cover area
3 FILTER  BULKY required → ① NO ✗ · ④ closed Sun ✗ → only ②
4 PRICE   ② 7,000 + value 0 + bulky 15,000 = 22,000
5 RANK    ⭐ only: ② Dar Cargo (car) 22,000

Buyer sees: 🚪 Dar Cargo (car) — 22,000. Cheap item, but bulky kept it off the bike.

C — intercity, multi-stop route, first/last mile

Laptop, shop in Mbeya → buyer in Morogoro town. Value 1,500,000, not bulky, Mon 10:00.

1 WHERE   different regions (intercity)
2 WHO     ①② don't reach Mbeya ✗ · ③ route: Mbeya(1) before Morogoro(3) ✓ · ④ nationwide ✓
3 FILTER  value ok · not bulky · both open Mon 10:00
4 PRICE   ③ Mbeya→Moro 8k+6k = 14,000 + value>1M 5,000 = 19,000 (collect at Morogoro Stand)
          ④ EMS >1M = 3% of 1.5M = 45,000 door-to-door 2–3 days
5 RANK    💰 ③ Shabiby 19,000 tomorrow · 📦 ④ EMS 45,000 to door 2–3 days

Buyer sees two groups:

🚌 Collect at station   Shabiby · Morogoro Stand (2 km) · tomorrow · 19,000
📦 To your door         EMS · 2–3 days · 45,000

Route matched automatically; priced only the Mbeya→Morogoro segment, not the whole line.

D — shipper rejects → auto-reassign (from §4.4)

From A, buyer picked ① 3,500.

Seller "Ready" → offer ① → ① TIMEOUT (busy)
  → 3,500 back in escrow · REASSIGNING · exclude ①
  → next = ② 7,000  → DEARER than 3,500
  → delivery money → buyer wallet, ask: "Mbezi Boda unavailable. Dar Cargo 7,000 (+3,500). Continue?"
  → buyer accepts → pays 3,500 from wallet → ② gets the job
  (if next were ≤3,500 → auto-assigned silently, no buyer action)

E — mixed cart, two shops (two shipments)

Cart: phone from Shop X (Kariakoo, Ilala, value 400k, not bulky) + blender from Shop Y (Mbezi, Ubungo, value 90k, not bulky). Buyer in Mikocheni (Kinondoni). Sat 11:00.

One shipment per shop (§4.1), priced independently:
  Shipment 1  X Kariakoo → Mikocheni (~9 km)
     WHO ② (Dar region) ✓ · ① ✗ (Ilala not in its areas)
     PRICE ② 7,000 + value 0 = 7,000
  Shipment 2  Y Mbezi → Mikocheni (~5 km)
     WHO ① ✓ (Ubungo+Kinondoni) · ② ✓
     PRICE ① 3,500 (cheapest) · ② 4,000
Checkout shows:
  🏪 Shop X · Dar Cargo       7,000
  🏪 Shop Y · Mbezi Boda      3,500
  Delivery total (2 deliveries) 10,500

Two shippers, two codes, two escrow releases. One slow shop never blocks the other.

F — free shipping (seller + NexGate stacked)

Shoes, Shop Z in Kinondoni → buyer in Kinondoni. Value 60,000, ~4 km, Fri 15:00. Shop Z offers free delivery in Kinondoni, pays up to 4,000. A NexGate weekend campaign in Dar pays up to 3,000.

Cheapest qualifying option: ① Mbezi Boda 4km = 3,500
  − seller pays (cap 4,000)  −3,500   → fully covered by seller
  − NexGate not needed
  = buyer pays 0
Shipment records: who_pays = seller 3,500

Buyer sees: 🚪 Free delivery · ~35 min (badge). Shipper still paid 3,500 in full from seller's earnings. If the trip were 9 km = 5,000: seller 4,000 + NexGate 1,000 = buyer still 0, split recorded.

One-line summary

Build the Location Service first (spec + data are ready). Then layer shipping on top: shippers are businesses with a wallet, described by service type × connection, answering one standard contract; they set their own coverage and pricing; money sits in escrow and releases on a delivery code; orders are accepted 24/7 with honest timing; and free shipping, hours and ratings slot into the same engine without changing it.

NexGate Location Service — Implementation Spec

For the implementer (Claude Code): read this whole file before writing code. Follow the existing conventions of the NexGate codebase (package layout, REST path style, auth/security, error format, ID type, DTO style, tests). Where this spec and the codebase conventions differ on style, follow the codebase. Where they differ on behaviour/rules, follow this spec. Keep it simple — no approval workflows, no extra services, no over-engineering.

0. Summary

The Location Service is a module inside the existing Spring Boot backend (not a microservice). It owns everything about where things are:

Shipping (providers, quotes, tracking) is out of scope — it will be built later on top of this service.

0.1 Where the Location Service is used across NexGate

It is the shared foundation for every feature that cares about where. Build the two core calls — resolve(pin) → ward/district/region and areaMatch(areaSet, pin-or-area) → bool — as reusable functions, because all of these call them:

Everything above reuses the same ward data and the same two functions — no new map work per feature. Only the two core calls are in scope now; the rest are listed so the API is designed to serve them.

1. Principles (non-negotiable)

  1. The pin (lat/lng) is the truth. Every saved location has a pin confirmed by the user on a map. No location is ever saved without coordinates.
  2. We take location only for a reason. No location request on app open, no background tracking for buyers or shops, no movement trails. Store only the pin the user confirmed.
  3. Hierarchy comes from our own data, not Google. Region/district/ward are computed on the backend from NBS ward shapes. Google is used only on the client (map display, place search, live label while placing the pin). The backend never calls Google and never stores Google text.
  4. Orders keep their own frozen copy of addresses. Editing or deleting a saved address never changes past orders.
  5. Simple. One module, plain SQL for spatial work, no Flyway, no version tracking, no JPA entity for the ward table.

2. Architecture

┌──────────────────────── CLIENTS (Android · iOS · Web) ────────────────────────┐
│  Pin screen: Google Map + Places search + live Google label (display only)    │
│  Sends: confirmed lat/lng + user text (landmark/note/phone/label)             │
└───────────────────────────────────────┬───────────────────────────────────────┘
                                        │ REST
┌───────────────────────────────────────▼───────────────────────────────────────┐
│                     NexGate Spring Boot backend                                │
│                                                                                │
│  ┌──────────────────────── location module ───────────────────────────────┐  │
│  │  WardResolver        pin → ward/district/region (PostGIS query)         │  │
│  │  LocationValidator   coverage, nearest-ward snap, device-distance check │  │
│  │  UserAddressService  saved addresses, default, duplicates, limits       │  │
│  │  RecentLocationSvc   last unsaved pins (max 5, 60 days)                 │  │
│  │  ShopLocationService one mandatory location per shop                    │  │
│  │  SnapshotFactory     frozen AddressSnapshot for orders                  │  │
│  │  WardDataSeeder      creates tables/indexes + loads ward file once      │  │
│  └────────────────────────────────┬────────────────────────────────────────┘  │
│                                   │ (internal Java calls)                      │
│  ┌────────────── orders / checkout ─────────┐   ┌──── shipping (FUTURE) ────┐ │
│  │ stores AddressSnapshot on each order      │──►│ reads snapshots only      │ │
│  └───────────────────────────────────────────┘   └───────────────────────────┘ │
└───────────────────────────────────────┬───────────────────────────────────────┘
                                        │ JDBC
┌───────────────────────────────────────▼───────────────────────────────────────┐
│  PostgreSQL + PostGIS (Docker image postgis/postgis)                           │
│  tz_wards · shop_locations · user_addresses · recent_locations                 │
└────────────────────────────────────────────────────────────────────────────────┘

   Ward data file (NOT in Git):  tz_wards_2022.geojson.gz  → mounted read-only into app container

Who decides what

              📍 confirmed pin (lat, lng)
             /                          \
   NBS ward shapes (ours, backend)     Google (client only)
   region, district, ward, codes        "Mlimani City, Sinza Mori…"
        │                                    │
     STORED (truth)                    shown on pin screen only, never sent/stored

3. Ward data

3.1 Source

3.2 File format (what the seeder reads)

{
  "type": "FeatureCollection",
  "crs": { "type": "name", "properties": { "name": "urn:ogc:def:crs:OGC:1.3:CRS84" } },
  "features": [
    {
      "type": "Feature",
      "properties": {
        "ward_id": 1, "nbs_code": "010111011",
        "reg_code": "01", "reg_name": "Dodoma",
        "dist_code": "01", "dist_name": "Kondoa",
        "counc_code": "11", "counc_name": "Halmashauri ya Wilaya ya Kondoa",
        "ward_code": "011", "ward_name": "Changaa"
      },
      "geometry": { "type": "Polygon", "coordinates": [[[35.6782, -4.736511], ...]] }
    }
  ]
}

3.3 Data facts the code must respect

Fact Consequence
Coordinates are [longitude, latitude] (GeoJSON order) ST_MakePoint(lng, lat) — longitude first. Most common bug.
Geometry is a mix of Polygon and MultiPolygon Always store with ST_Multi(...) into a MultiPolygon column.
ward_code alone is NOT unique; even nbs_code repeats for 5 wards (NBS data issue) ward_id (1..4344) is the primary key. nbs_code is informational, not unique.
Shapes stop at shorelines (sea, Lake Victoria, etc.) Pins on beaches/jetties may fall outside every ward → nearest-ward fallback (§6).
31 regions, ~4,344 wards. Dar es Salaam has 5 councils (Ilala, Kinondoni, Temeke, Ubungo, Kigamboni) Expected counts for sanity tests.

3.4 District & region come from the ward rows — no separate files

There is no separate district or region boundary table. Every ward row already carries its council, district and region names and codes, so a single ST_Contains lookup returns all levels at once:

pin → ward (Kariakoo) → already has dist_name=Ilala, reg_name=Dar es Salaam, codes included

-- district outlines (view or materialized view, optional)
SELECT reg_code, reg_name, dist_code, dist_name, ST_Union(geom) AS geom
FROM tz_wards GROUP BY reg_code, reg_name, dist_code, dist_name;

-- region outlines
SELECT reg_code, reg_name, ST_Union(geom) AS geom
FROM tz_wards GROUP BY reg_code, reg_name;

Use counc_code as well if councils (halmashauri) matter for coverage; the ward rows carry it too.

4. Infrastructure

4.1 Docker

services:
  db:
    image: postgis/postgis:16-3.4        # match current PG major version
  app:
    volumes:
      - /opt/nexgate/geo:/app/geo:ro      # host folder holding tz_wards_2022.geojson.gz
    environment:
      GEO_WARDS_FILE: /app/geo/tz_wards_2022.geojson.gz

4.2 Config

# path to .geojson or .geojson.gz ; empty/missing → seeder logs WARN and skips
geo.wards-file=${GEO_WARDS_FILE:./data/geo/tz_wards_2022.geojson.gz}

4.3 No Flyway, no version tracking

Schema for this module is created by the WardDataSeeder at startup using idempotent SQL (IF NOT EXISTS). It runs after Hibernate initialises (use ApplicationRunner or ApplicationReadyEvent).

5. Database

5.1 Entity relationships

erDiagram
    TZ_WARDS ||--o{ SHOP_LOCATIONS : "resolved to"
    TZ_WARDS ||--o{ USER_ADDRESSES : "resolved to"
    TZ_WARDS ||--o{ RECENT_LOCATIONS : "resolved to"
    USERS ||--o{ USER_ADDRESSES : owns
    USERS ||--o{ RECENT_LOCATIONS : has
    SHOPS ||--|| SHOP_LOCATIONS : "has exactly one"
    ORDERS ||--|| ADDRESS_SNAPSHOT : "pickup (frozen copy)"
    ORDERS ||--|| ADDRESS_SNAPSHOT : "drop-off (frozen copy)"

Addresses store ward_id and copies of the names/codes (denormalised) so reads never need a join and display stays stable.

5.2 tz_wards (created + filled by seeder)

CREATE EXTENSION IF NOT EXISTS postgis;

CREATE TABLE IF NOT EXISTS tz_wards (
    ward_id     INTEGER PRIMARY KEY,
    nbs_code    VARCHAR(16)  NOT NULL,
    reg_code    VARCHAR(4)   NOT NULL,
    reg_name    VARCHAR(100) NOT NULL,
    dist_code   VARCHAR(4)   NOT NULL,
    dist_name   VARCHAR(100) NOT NULL,
    counc_code  VARCHAR(4)   NOT NULL,
    counc_name  VARCHAR(200) NOT NULL,
    ward_code   VARCHAR(8)   NOT NULL,
    ward_name   VARCHAR(100) NOT NULL,
    geom        geometry(MultiPolygon, 4326) NOT NULL
);
CREATE INDEX IF NOT EXISTS idx_tz_wards_geom ON tz_wards USING GIST (geom);
CREATE INDEX IF NOT EXISTS idx_tz_wards_names ON tz_wards (reg_name, dist_name, ward_name);

5.3 Location tables (logical schema — use project ID type & audit conventions)

shop_locations — exactly one per shop

column type rule
id project ID type PK
shop_id FK → shops unique
lat, lng double required, rounded to 6 decimals
ward_id int resolved by backend
reg_name, dist_name, ward_name, nbs_code text copied from ward
match_type enum CONTAINED / NEAREST from resolver
landmark text (≤ 300) required ("Near Shekilango stop, above Vodashop, 1st floor")
building text (≤ 100) optional ("Shop 12")
pickup_phone text required, E.164 (+255…)
official_address text (≤ 100) optional (Anwani za Makazi)
photo_url text optional (shop front photo, uses existing media upload)
created_at, updated_at timestamp

user_addresses — buyer's saved addresses (0..10 per user)

column type rule
id project ID type PK
user_id FK → users
label_type enum HOME / WORK / OTHER HOME and WORK max one each per user
custom_label text (≤ 40) required when OTHER ("Mama's place")
lat, lng double required, 6 decimals
ward_id, reg_name, dist_name, ward_name, nbs_code, match_type resolved by backend
note text (≤ 300) optional note for rider ("Black gate, call on arrival")
receiver_name text defaults to user's name
receiver_phone text defaults to user's phone, E.164
is_default boolean at most one true per user
last_used_at timestamp updated when used in an order
created_at, updated_at timestamp

recent_locations — unsaved delivery pins (max 5 per user, expire after 60 days)

column type rule
id project ID type PK
user_id FK → users
lat, lng, ward_id, reg_name, dist_name, ward_name, match_type as above
note, receiver_name, receiver_phone as used in that order
last_used_at timestamp

Indexes created by seeder after Hibernate (idempotent):

CREATE UNIQUE INDEX IF NOT EXISTS ux_shop_locations_shop ON shop_locations (shop_id);
CREATE INDEX IF NOT EXISTS idx_shop_locations_geog ON shop_locations
    USING GIST ((ST_SetSRID(ST_MakePoint(lng, lat), 4326)::geography));   -- for future "near me"
CREATE INDEX IF NOT EXISTS idx_user_addresses_user ON user_addresses (user_id);
CREATE UNIQUE INDEX IF NOT EXISTS ux_user_addresses_default ON user_addresses (user_id) WHERE is_default;
CREATE UNIQUE INDEX IF NOT EXISTS ux_user_addresses_home ON user_addresses (user_id) WHERE label_type = 'HOME';
CREATE UNIQUE INDEX IF NOT EXISTS ux_user_addresses_work ON user_addresses (user_id) WHERE label_type = 'WORK';
CREATE INDEX IF NOT EXISTS idx_recent_locations_user ON recent_locations (user_id, last_used_at DESC);

(If the project creates these tables itself via its own mechanism, keep the indexes in the seeder anyway.)

5.4 AddressSnapshot (frozen copy stored on orders)

Not a table owned by this module. The orders module stores it (e.g. a jsonb column pickup_snapshot / dropoff_snapshot, or embedded columns — follow project convention). Immutable once stored.

{
  "lat": -6.774512, "lng": 39.241871,
  "wardId": 1131, "nbsCode": "070113062",
  "regionName": "Dar es Salaam", "districtName": "Kinondoni", "wardName": "Kijitonyama",
  "matchType": "CONTAINED",
  "label": "Home",                         // null if unsaved
  "landmarkOrNote": "Black gate, call on arrival",
  "building": null,
  "contactName": "Kibuti", "contactPhone": "+2557XXXXXXXX",
  "sourceType": "USER_ADDRESS",            // USER_ADDRESS | NEW_PIN | SHOP_LOCATION
  "sourceId": "…",                         // id of saved address/shop location, null for NEW_PIN
  "capturedAt": "2026-10-08T12:30:00Z"
}

6. Pin resolution (core algorithm)

 input: lat, lng
   │
   ├─ basic checks: lat ∈ [-90,90], lng ∈ [-180,180], not (0,0) ── fail → 400 INVALID_COORDINATES
   │
   ├─ round to 6 decimals
   │
   ├─ Query A: ward whose shape CONTAINS the point
   │     found → matchType = CONTAINED, distanceM = 0  ───────────────────────► return ward
   │
   ├─ Query B: nearest ward within 500 m (shoreline, beach, jetty, border gaps)
   │     found → matchType = NEAREST, distanceM = n  ─────────────────────────► return ward
   │
   └─ nothing → OUTSIDE_COVERAGE (sea, lake, outside Tanzania)

-- Query A (uses GIST index)
SELECT ward_id, nbs_code, reg_name, dist_name, counc_name, ward_name
FROM tz_wards
WHERE ST_Contains(geom, ST_SetSRID(ST_MakePoint(:lng, :lat), 4326))
LIMIT 1;

-- Query B (only if A returns nothing)
SELECT ward_id, nbs_code, reg_name, dist_name, counc_name, ward_name,
       ST_Distance(geom::geography, ST_SetSRID(ST_MakePoint(:lng, :lat), 4326)::geography) AS distance_m
FROM tz_wards
WHERE ST_DWithin(geom::geography, ST_SetSRID(ST_MakePoint(:lng, :lat), 4326)::geography, 500)
ORDER BY distance_m
LIMIT 1;

Point exactly on a border → whichever ward Query A returns is fine. Constant: NEAREST_WARD_MAX_METERS = 500.

6.1 Validation rules

Check Applies to Result
Invalid coordinates all block INVALID_COORDINATES
No ward within 500 m all block OUTSIDE_COVERAGE ("We don't deliver here yet")
Matched by NEAREST all allow, matchType=NEAREST (info only)
Pin > 1 km from device position (client sends optional deviceLat/deviceLng) shop only allow, return warning FAR_FROM_DEVICE with distance; client asks "Your pin is 3.2 km from where you are. Is this your shop?"
Saved address within 50 m of another saved address of same user buyer save 409 NEAR_DUPLICATE with the existing address; client asks "This looks like 🏠 Home. Use it?"; client may resend with allowNearDuplicate=true
More than 10 saved addresses buyer save block ADDRESS_LIMIT_REACHED
Second HOME or WORK buyer save/edit block LABEL_ALREADY_USED

Client-only checks (not backend): GPS accuracy circle, minimum zoom before confirm, satellite toggle.

7. Business rules

7.1 Shop location

7.2 Buyer addresses

7.3 Recent locations

7.4 Orders / snapshots

7.5 Account deletion

Deletes all user_addresses and recent_locations of that user. Order snapshots remain (order records).

8. Privacy & visibility

Data Buyer Seller Rider / delivery provider Third parties
Buyer saved addresses / recents own only ❌ ❌ ❌
Order drop-off area (ward, district, region) ✅ ✅ ✅ ❌
Order drop-off exact pin + note + phone ✅ only if seller delivers itself (sellerDelivers=true) ✅ for that shipment only ❌
Shop location (pin, landmark, ward) ✅ public ✅ ✅ ❌
Shop pickup phone after order ✅ ✅ ❌

Implement as two snapshot views: AddressSnapshotPublicView (area only) and AddressSnapshotFullView. Analytics/reports aggregate by ward/district only — never per person. Never log full coordinates together with user identifiers at INFO level.

9. REST API

Paths shown as examples — adapt prefix/style/auth to the existing project. All endpoints require authentication except GET /shops/{id}/location (public view).

9.1 Resolve (used live by pin screen after the map stops moving — debounce ~400 ms client side)

GET /api/v1/locations/resolve?lat=-6.8190&lng=39.2768

200 { "covered": true, "matchType": "CONTAINED", "distanceM": 0,
      "ward": { "wardId": 1146, "nbsCode": "070214112", "wardName": "Kariakoo",
                "districtName": "Ilala", "councilName": "Halmashauri ya Jiji la Dar es Salaam",
                "regionName": "Dar es Salaam" },
      "areaLabel": "Kariakoo, Ilala, Dar es Salaam" }
200 { "covered": false, "reason": "OUTSIDE_COVERAGE" }

Nothing is stored by this call.

9.2 Buyer addresses

Method Path Notes
GET /api/v1/me/addresses list, default first, then last_used_at desc
POST /api/v1/me/addresses create (body below)
PUT /api/v1/me/addresses/{id} update (same body)
DELETE /api/v1/me/addresses/{id} hard delete
POST /api/v1/me/addresses/{id}/default make default
GET /api/v1/me/recent-locations max 5, ≤ 60 days
DELETE /api/v1/me/recent-locations/{id} remove one
DELETE /api/v1/me/recent-locations clear all 
POST /api/v1/me/addresses
{ "lat": -6.774512, "lng": 39.241871,
  "labelType": "OTHER", "customLabel": "Mama's place",
  "note": "Black gate, call on arrival",
  "receiverName": null, "receiverPhone": null,      // null → use profile
  "makeDefault": false, "allowNearDuplicate": false }

9.3 Shop location

Method Path Notes
GET /api/v1/shops/{shopId}/location public view (no phone unless authorised)
PUT /api/v1/shops/{shopId}/location create or replace; owner only 
PUT /api/v1/shops/{shopId}/location
{ "lat": -6.770901, "lng": 39.229410,
  "landmark": "Near Shekilango stop, above Vodashop, 1st floor",
  "building": "Shop 12", "pickupPhone": "+2557XXXXXXXX",
  "officialAddress": null, "photoUrl": null,
  "deviceLat": -6.7712, "deviceLng": 39.2291 }       // optional, for FAR_FROM_DEVICE warning
→ 200 { ...location..., "warnings": [ { "code": "FAR_FROM_DEVICE", "distanceM": 3200 } ] }

9.4 Internal Java API (for orders/shop modules — not REST)

ResolveResult resolve(double lat, double lng);
boolean hasShopLocation(ShopId shopId);
AddressSnapshot snapshotFromShop(ShopId shopId);
AddressSnapshot snapshotFromAddress(UserId userId, AddressId addressId);   // also bumps last_used_at
AddressSnapshot snapshotFromRecent(UserId userId, RecentId recentId);
AddressSnapshot snapshotFromNewPin(UserId userId, NewPinRequest req);      // req.saveForLater → creates address, else records recent

9.5 Error codes

INVALID_COORDINATES, OUTSIDE_COVERAGE, NEAR_DUPLICATE (409, includes existing address), ADDRESS_LIMIT_REACHED, LABEL_ALREADY_USED, SHOP_LOCATION_REQUIRED (thrown by shop publish), NOT_FOUND, FORBIDDEN. Use the project's existing error response format.

10. WardDataSeeder (startup)

App starts (after Hibernate)
  │
  ├─ 1. CREATE EXTENSION IF NOT EXISTS postgis          (log clear error if not permitted)
  ├─ 2. CREATE TABLE IF NOT EXISTS tz_wards …  + indexes
  ├─ 3. CREATE INDEX IF NOT EXISTS … on location tables (§5.3)
  │
  ├─ 4. BEGIN; SELECT pg_advisory_xact_lock(<constant>)   ← only one container seeds
  │      SELECT count(*) FROM tz_wards
  │        ├─ > 0  → COMMIT, done (normal startup, instant)
  │        └─ = 0  → file exists?
  │                    ├─ no  → WARN "ward file not found at …; ward lookup disabled", COMMIT, continue startup
  │                    └─ yes → stream features (Jackson streaming parser, gzip if *.gz)
  │                             batch insert 200 rows:
  │                             INSERT INTO tz_wards (…, geom)
  │                             VALUES (…, ST_Multi(ST_SetSRID(ST_GeomFromGeoJSON(?), 4326)))
  │                             ON CONFLICT (ward_id) DO NOTHING
  │                             COMMIT; ANALYZE tz_wards
  │                             log "Loaded N wards in X s" (expect 4344)
  │
  └─ 5. If wards were just loaded AND user_addresses/shop_locations/recent_locations already have rows
         → re-resolve all of them (update ward_id + name copies + match_type). Order snapshots untouched.

Rules:

11. Client behaviour (Android · iOS · Web)

11.1 Location permission

┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐
┆           📍                  ┆
   Use your location?
┆ We use it once to place your  ┆
   pin faster. You can also
┆ search or move the map.       ┆
  ┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐
┆ ┆   Use my location         ┆ ┆   → OS permission prompt
  └ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘
┆        Not now              ┆     → stay on map, no prompt
└ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘

11.2 Pin screen (shared component — shop, buyer, add-address)

Behaviour:

  1. Fixed centre pin, the map moves (Bolt/Uber pattern). Pin lifts while dragging, drops when the map stops.
  2. Start position: accurate GPS → last used location → centre of user's city. Never whole-country view.
  3. Map / Satellite toggle (satellite matters — many streets unnamed).
  4. GPS accuracy circle; if accuracy > 100 m show "Location is approximate — move the map to your exact spot".
  5. Confirm disabled until zoom ≥ 17 (street level). Hint: "Zoom in to place exactly".
  6. Search (Google Places) only moves the map: "Now move the map to the exact entrance".
  7. When map stops (debounce ~400 ms): show Google label + call /locations/resolve. If covered=false → disable Confirm, show "We don't deliver here yet".
┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐
  ←  Shop location     Step 3/4
┆ ┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐ ┆
  ┆ 🔍 Search place or area   ┆
┆ └ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘ ┆
  ┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐
┆ ┆ [Map|Satellite]           ┆ ┆
  ┆                           ┆
┆ ┆        ( ◌ )  ← accuracy  ┆ ┆
  ┆          📍  fixed centre ┆
┆ ┆        move the map       ┆ ┆
  ┆                    [◎]    ┆   [◎] = use my location
┆ └ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘ ┆
  ⚠ Zoom in to place exactly
┆   (shown until zoom ≥ 17)     ┆
  📍 Sinza, Ubungo, Dar es Salaam      ← Google label (display only)
┆ ┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐ ┆
  ┆   Confirm location   →    ┆
┆ └ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘ ┆
└ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘

11.3 Shop flow (mandatory, step in shop creation)

┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐
  ←  Shop location     Step 3/4
┆ ┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐ ┆
  ┆ [mini map 📍]   Change    ┆
┆ ┆ Makurumla, Ubungo, Dar    ┆ ┆   ← from /resolve (NBS)
  └ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘
┆ Directions / landmark *       ┆
  ┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐
┆ ┆ Near Shekilango stop,     ┆ ┆
  ┆ above Vodashop, 1st floor ┆
┆ └ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘ ┆
  Building / shop no. (optional)
┆ ┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐ ┆
  ┆ Shop 12                   ┆
┆ └ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘ ┆
  Pickup contact phone *
┆ ┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐ ┆
  ┆ +255 7XX XXX XXX          ┆
┆ └ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘ ┆
  Official address (optional)
┆ ┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐ ┆
  ┆ Anwani za Makazi          ┆
┆ └ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘ ┆
  📷 Add shop front photo (optional)
┆ ┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐ ┆
  ┆   Save & continue    →    ┆
┆ └ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘ ┆
└ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘

If response has FAR_FROM_DEVICE → dialog "Your pin is 3.2 km from where you are. Is this your shop?" [Yes, it's correct] [Adjust pin].

11.4 Buyer delivery flow (pin only, Bolt style)

Checkout — choose where

┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐
  Deliver to
┆ ┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐ ┆
  ┆ ● 🏠 Home      (default)   ┆
┆ ┆   Mbezi Juu, Ubungo       ┆ ┆
  ┆ ○ 💼 Work                  ┆
┆ ┆   Kivukoni, Ilala         ┆ ┆
  ┆ ○ ⭐ Mama's place          ┆
┆ ┆   Tabata, Ilala           ┆ ┆
  ├ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┤
┆ ┆ Recent                    ┆ ┆
  ┆ ○ 🕘 Kijitonyama   [Save]  ┆
┆ ├ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┤ ┆
  ┆ ＋ New location (pin)      ┆
┆ └ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘ ┆
         Manage addresses
└ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘

First-time buyer with nothing saved → goes straight to the pin screen.

New location — full map + bottom sheet

┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐
  ←  Deliver to       [Sat]
┆                               ┆
          FULL MAP
┆           📍                  ┆
                         [◎]
┆ ┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐ ┆
  ┆ 🔍 Search                 ┆
┆ ┆ 🏠 Home     Mbezi Juu      ┆ ┆   ← tap jumps the pin there
  ┆ 💼 Work     Kivukoni       ┆
┆ ┆ 🕘 Recent   Kijitonyama    ┆ ┆
  ├ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┤
┆ ┆ 📍 Mikocheni, Kinondoni    ┆ ┆
  ┆ [ Deliver here → ]        ┆
┆ └ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘ ┆
└ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘

Quick confirm sheet

┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐
  📍 Mikocheni, Kinondoni
┆                               ┆
  Note for rider (optional)
┆ ┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐ ┆
  ┆ Black gate, call on arrival┆
┆ └ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘ ┆
  Receiver: Me (+255 7XX…)  ✎        ← "Someone else" → name + phone
┆                               ┆
  [ ] Save as  🏠  💼  ✎             ← labels shown only when ticked
┆ ┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐ ┆
  ┆      Continue  →          ┆
┆ └ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘ ┆
└ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘

Profile — manage addresses

┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐
  ←  My addresses
┆ ┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐ ┆
  ┆ 🏠 Home  ✓default     ⋮   ┆
┆ ┆ Mbezi Juu, Ubungo         ┆ ┆
  ├ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┤
┆ ┆ 💼 Work               ⋮   ┆ ┆
  ┆ Kivukoni, Ilala           ┆
┆ ├ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┤ ┆
  ┆ ⭐ Mama's place        ⋮   ┆
┆ ┆ Tabata, Ilala             ┆ ┆
  └ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘
┆   ⋮ = Edit pin · Rename ·     ┆
    Set default · Delete
┆ ┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐ ┆
  ┆   ＋ Add address           ┆
┆ └ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘ ┆
  🕘 Clear recent locations
└ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘

Optional secondary onboarding (buyer)

┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐
┆           📦                  ┆
   Faster checkout?
┆  Add your home address now    ┆
   and skip it at checkout.
┆ ┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐ ┆
  ┆      Add address          ┆      → pin screen → quick confirm (Save always on)
┆ └ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘ ┆
           Maybe later
└ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘

Area lines shown after saving (lists, checkout) are built from NBS names (ward, district) plus the user's label — never from Google text.

12. Flows

12.1 Shop sets location

sequenceDiagram
    actor Owner
    participant App
    participant Google as Google Maps/Places (client)
    participant API as Location module
    participant DB as PostGIS
    Owner->>App: Step 3 "Shop location"
    App->>Owner: Explainer → tap "Use my location"
    App->>App: OS permission (while in use), one GPS reading
    Owner->>App: Move map under fixed pin, zoom ≥ 17
    App->>Google: label for map centre (display only)
    App->>API: GET /locations/resolve?lat&lng
    API->>DB: ST_Contains / nearest ≤ 500 m
    DB-->>API: ward, district, region
    API-->>App: covered=true, areaLabel
    Owner->>App: Confirm → landmark, phone, (building, photo)
    App->>API: PUT /shops/{id}/location (+deviceLat/Lng)
    API->>DB: resolve again, upsert shop_locations
    API-->>App: saved (+ FAR_FROM_DEVICE warning if > 1 km)

12.2 Buyer checkout with a new pin

sequenceDiagram
    actor Buyer
    participant App
    participant Orders as Orders/Checkout
    participant Loc as Location module
    participant DB as PostGIS
    Buyer->>App: Checkout → "＋ New location"
    Buyer->>App: Place pin, note, receiver, [Save?]
    App->>Loc: GET /locations/resolve (live while moving)
    Buyer->>App: Continue / Pay
    App->>Orders: place order { newPin, saveForLater }
    Orders->>Loc: snapshotFromNewPin(user, req)
    Loc->>DB: resolve ward
    alt saveForLater = true
        Loc->>DB: insert user_addresses (rules §7.2)
    else
        Loc->>DB: upsert recent_locations (max 5, 60 days)
    end
    Loc-->>Orders: AddressSnapshot (frozen)
    Orders->>DB: store order + pickup & drop-off snapshots

12.3 Shop publish guard

Shop "Publish" → shopModule calls location.hasShopLocation(shopId)
   ├─ true  → publish
   └─ false → 400 SHOP_LOCATION_REQUIRED → app opens Shop location step

13. Out of scope (do NOT build now)

14. Acceptance tests

14.1 Ward resolution (integration test against loaded data — these were verified against the file)

Place lat lng Expected ward District Region
Kariakoo market -6.8190 39.2768 Kariakoo Ilala Dar es Salaam
Ubungo bus terminal -6.7889 39.2083 Ubungo Ubungo Dar es Salaam
JNIA airport -6.8781 39.2026 Kipawa Ilala Dar es Salaam
Posta / city centre -6.8160 39.2900 Kivukoni Ilala Dar es Salaam
Stone Town -6.1622 39.1887 Shangani Mjini Mjini Magharibi
Arusha clock tower -3.3700 36.6940 Sekei Arusha Arusha
Mwanza centre -2.5164 32.9006 Nyamagana Nyamagana Mwanza
Mbeya town -8.9094 33.4608 Ruanda Mbeya Mbeya
Dodoma centre -6.1722 35.7395 Majengo Dodoma Dodoma
Indian Ocean off Dar -6.80 39.40 — OUTSIDE_COVERAGE
Nairobi -1.2864 36.8172 — OUTSIDE_COVERAGE

Also: SELECT count(*) FROM tz_wards = 4344; SELECT count(DISTINCT reg_name) = 31. Use Testcontainers with postgis/postgis image if the project already uses Testcontainers; otherwise follow project test setup.

14.2 Rules

15. Build order

  1. Docker: switch DB to postgis/postgis (same PG major), mount /opt/nexgate/geo, add config, .gitignore data/geo/.
  2. WardDataSeeder + WardResolver + GET /locations/resolve + tests §14.1. ← foundation
  3. Shop location (entity, PUT/GET, hasShopLocation, publish guard).
  4. Buyer addresses + recents (+ rules tests).
  5. AddressSnapshot + checkout integration + privacy views.
  6. Clients: shared pin-screen component, shop step, checkout picker, manage addresses, optional onboarding.

NexGate Shipping Service — Development guide

Status: design agreed in discussion (2026-10-12), not built yet. Built on the Location Service (wards, shop locations, user addresses, frozen places — see commerce_logistics_changes.md). Source specs: doc-hub Logistics Service book (location spec + commerce/location/logistics master guide). Where this document and the master guide differ, this document wins (it records our decisions).

Rule of thumb for everything below: simple over clever. Shipping prices are placeholders (0) until this service is built; build what is decided, keep a visible list of what is not.

1. Principles

  1. Two ways to get an order: PICKUP or DELIVERY, chosen per shop. The shipping service owns both.
  2. One shop's order = one parcel. A cart with three shops = three parcels, three fulfillments.
  3. User addresses are places only (pin, label, directions). Order data — who receives, notes — lives on the order, never in the address book.
  4. Everything about places is frozen on the order when the checkout session is created. Later edits to a shop location, an address or a price never change an existing order.
  5. Money sits in escrow and moves on proof (codes), never on trust.
  6. Shippers describe their own coverage, prices and times. NexGate never forces one model.
  7. No manual approval queues. Trust comes from documents, codes, reviews and automatic rules.
  8. Orders are accepted 24/7; timing is honest. Closed hours delay work, never the sale.
  9. Pickup and delivery are designed together. Every feature must say what it does for a pickup order.

2. Big picture

MESSAGES (everyone talks only to NexGate; the SHIPPING AGREEMENT is the deal they all sign — §4.8)
  buyer   ── estimation / quotation / agreement / pay ──►┐
  seller  ── accept / ready / verify pickup code ───────►├── NexGate ── escrow: items + legs
  shipper ◄── offers ──  ── accept / status / code ─────►┘   (native: app · integrated: API)

PARCEL (physical, with the code that unlocks each handover)
  pickup:    shop ──[buyer's code]──► buyer
  delivery:  shop ──[pickup code]──► shipper ──[delivery code]──► buyer
  chain:     shop ──► shipper 1 ──[handover code]──► shipper 2 ──► … ──► buyer

Package layout (new top-level shipping_service/, next to location_service/)

Package Owns
fulfillment/ one record per shop order: PICKUP or DELIVERY, frozen places, receiver, note, status, codes, timers. (Replaces the Step-4 e_commerce/fulfillment JSON — the order links to this record.)
business/ native shippers ("delivery businesses"): KYC, Service Setup, coverage, pricing, hours, stations, reviews
providers/ integrated shippers: one adapter per provider
engine/ estimation + quotations: coverage, pricing, ETA, chains, ranking — native and integrated together
jobs/ offers, accept / reject, reassignment, status steps, handovers

Shared pieces used across: opening_hours (shops, businesses, stations), the area picker and frozen places from location_service.

3. Fulfillment: pickup and delivery

3.1 Pickup

placed → accepted → ready → collected → completed
exits: cancelled (buyer before accept, or seller) · expired (14 days)

3.2 Delivery (door-to-door)

placed → accepted → ready → shipper accepted → heading to the shop → picked up → on the way → delivered → completed (the same accepted / ready / completed as pickup; "ready" is when the offers go out)

Heading to the shop — the shipper taps it when they set out. It marks when cancelling the shipping starts to cost the buyer (§3.4a).

3.3 Delivery (station)

placed → accepted → ready → shipper accepted → heading to the shop → dropped at station → in transit → at destination station → collected → completed (the parcel always starts with a collection at the shop — by a door shipper, or by the station business itself when it collects from shops, §7.2a) (the buyer collects at the station; station staff enter the buyer's code)

3.4 Switching (buyer only, many times allowed within the rules)

From → to Allowed Money
Pickup → delivery any time before the buyer collects fresh quotes at today's prices; buyer pays the delivery fee from the wallet into new leg part(s); if the order is already ready, the offer goes to the shipper at once
Delivery → pickup before pickup (same rules as cancelling the shipping, §3.4a) leg part(s) refunded, minus the wasted-trip fee if a shipper is already heading to the shop

3.4a Cancelling (buyer)

Situation Buyer can
Before the seller accepts cancel the whole order — full refund
After the seller accepts, no shipper accepted yet cancel the shipping (keep the order): pickup (delivery refunded) or a new delivery proposal (new quotation → new agreement; pay or get back the difference)
A shipper accepted, not heading to the shop yet cancel the shipping → pickup or a new proposal; free (like Bolt); the shipper is released and told (no reliability effect on them)
A shipper is heading to the shop cancel the shipping with a wasted-trip fee paid by the buyer: native = 50% of that leg's cost, Bolt = Bolt's own cancellation charge
Parcel picked up no cancelling the shipping — only a destination change (§4.8) or, in a chain, stop at the next meeting point (legs not started are refunded)
Chain failed — a shipper didn't accept and no replacement was found, or the buyer declined the dearer proposal drop the shipping → pickup, a new delivery proposal, end the chain earlier — or cancel the whole order (full refund, stock back; not the buyer's fault)

Rule: whoever causes the cost pays it. Switching delivery → pickup after the seller signed does not need the seller to sign again (they agreed to hand the order over; who collects is the buyer's choice) — the seller is told.

3.5 What every fulfillment record holds

type · pickup place (the shop, frozen) · drop-off place (delivery, frozen) · receiver (name + phone; for pickup = who collects; default = the buyer) · parcel number (§11) · planned pickup time (pickup, optional) · note (this order only) · the agreement (legs, shippers, meeting points, costs, ETAs) · status · codes · who paid what (free shipping split) · timestamps of every step.

4. Choosing: estimation → quotation → agreement

4.1 Three stages

Stage What Where Can change? Lifetime
Shipping estimation a hint: cost {from,to}, eta {from,to} product cards and lists — cached, not stored
Shipping quotation the proposal: recommended chain (legs, shippers, meeting points, cost, ETA) + alternatives per leg add-to-cart / buy-now sheet, the cart yes — destination, shipper per leg, meeting point, pickup ↔ delivery prices held 5 days while the parcel is unchanged
Shipping agreement the deal created at checkout from the quotation editable on the checkout screen until paid locked once paid for the order's whole life 
card "🚚 20,000 – 35,000 to Mbeya"          ← estimation
 └ sheet / cart: QUOTATION — buyer edits ("collect at Mbeya Bus Stand", "use Abood")
     └ checkout: AGREEMENT — still editable before paying
         └ paid: LOCKED — shippers bound to these prices and legs

Quotation rules

Agreement rules

4.2 Destination (where the quotation ends)

The start is always the shop where the product is. The buyer picks the end — no saved address needed: saved address · recent pin · "use my location" · search a known place (Google Places in the app, e.g. "Mbeya bus stand") · drop a pin. All end as a confirmed pin that we resolve (Google only in the app; we never store Google's text; the buyer may add their own label).

Meeting-point recognition: a destination pin within 1 km of a station → the quotation offers "🚌 Collect at , " (no last-mile leg) and "🚪 Deliver to this exact pin" (if covered).

4.3 Add-to-cart / buy-now sheet

Deliver to (header address, changeable) · quantity · Pickup or Delivery with the ⭐ quotation pre-selected and "change" (edit legs / destination).

POST /api/v1/e-commerce/cart/add
{
  "productId": "…", "quantity": 2,
  "fulfillment": { "type": "DELIVERY", "quotationId": "…" },   // the SHOP's choice
  "dropoff": { "addressId": "…" }                               // only if changed in the sheet: the CART's destination
}

4.4 Cart rules

4.5 Estimation

POST /api/v1/shipping/estimations
{ "dropoff": { "addressId": "…" }, "productIds": ["…", "…"] }
→ [ { "productId": "…", "cost": { "from": 3500, "to": 7000 }, "eta": { "from": "30 min", "to": "2 h" },
      "freeDelivery": false, "pickupArea": "Ubungo, Ubungo, Dar es Salaam" } ]

cost range = cheapest → dearest of the sensible options (dominated / outliers removed). No shipper → cost: null (card shows "Pickup only"). Cached shop-area → buyer-area (Redis ~1 h). The app asks with the address in its header; list and feed responses are unchanged. Prices are always called cost (cost, originalCost when a discount applies).

4.6 What the app keeps vs the server

Rule: anything that affects money or a promise stays on the server; anything that is only "where the user was" can live in the app.

The app may keep (no backend storage) Why it's fine
Header "Deliver to" for card estimations sent with every estimation request; estimations are only hints
Last destination used / last map position convenience for the pin screen
A sheet in progress (before tapping Add) nothing committed yet
Recently searched places the search runs in the app (Google)
UI preferences (list / map, "See all") personal display
An unsaved pin, to offer it again on the pin screen never becomes a backend recent unless the order is paid
Must stay on the server Why
The cart's destination + each shop's quotation quotations hold prices 5 days — a promise; must work on any device
Agreements bind shippers and money
Saved addresses, recent pins shared across devices, used when ordering

4.7 Multi-shipper per order

One parcel can travel through up to 3 shippers (legs), e.g.:

Leg 1 🚪 Kibuti Express  Mlimani City shop → Magufuli Terminal (Dar)   3,500   2–3 h
Leg 2 🚌 Shabiby         Magufuli Terminal → Mbeya Bus Stand          21,000   1 day
Leg 3 🚪 Mbeya Riders    Mbeya Bus Stand   → buyer's door              2,500   1–2 h

4.8 The shipping agreement — parties, signatures, changes

The agreement is the deal every party signs: buyer, seller and every shipper on the route. It is its own entity and controls every important action on a parcel: one place decides whether a change is allowed, one history records who proposed and who approved, and money moves only on an agreement event (no other code path releases or refunds an escrow part).

Signatures — each party already says yes somewhere in the flow:

Party Signs when Agrees to
Buyer pays at checkout items, destination, legs, cost
Seller accepts the order (within 24 opening hours) pack it and hand it over
Each shipper accepts the offer at Ready carry their leg (capacity — the price came from their own price table)

The buyer can be charged a fixed price before the shippers sign because each shipper's price table is a standing offer; a shipper's signature means "I'll carry it", not "I accept the price".

States:

DRAFT      created at checkout; the buyer can still edit
PENDING    the buyer paid → waiting for the seller, then the shippers
AGREED     everyone signed → binding on all; the parcel can move
DONE       buyer confirmed "✓ It's what I ordered" → all escrow parts released
CANCELLED  refunded as the cancel rules say (§3.4a)

Changes. A change only re-opens the signatures it affects (swapping leg 2 never asks the seller or leg 1). Three kinds:

  1. Affects only me → applied at once; the others are told.
  2. Affects others → proposed; the affected parties approve; silence falls back to a written default by the deadline (so one silent party never blocks the deal).
  3. Rule-based (NexGate / the system) → applied under the rule, logged.
Change Kind Who must approve No answer by the deadline
Buyer edits before paying (DRAFT) 1 — —
Buyer cancels the whole order before the seller signs 1 — —
Seller cancels (pickup before collected / delivery before Ready; pop-up "I informed the buyer", §3.1) 1 — (buyer notified at once) —
Buyer cancels the shipping / switches to pickup (before pickup) 1 — (shipper released and told; fee if heading to the shop) —
Buyer changes the destination before any shipper accepted 1 — (re-quoted at today's prices) —
Buyer changes the destination after a shipper accepted 2 the shipper(s) whose leg changes original destination stays
Accepted leg's time moves > 4 h 2 that shipper (re-confirm) treated as "no" → leg reassigned
Reassignment — same / cheaper and not later 3 — —
Reassignment — dearer / slower / nobody 2 the buyer 24 h, then automatic switch to pickup
Chain not fully accepted 24 h after Ready 2 the buyer 24 h, then automatic switch to pickup
Bulky mismatch 3 — (seller pays the difference automatically) —
Admin action (§6.7.2) 3 — (reason required, audit-logged) —

Destination change (buyer) — when it is allowed (like AliExpress: the app shows "Change delivery location" only in these statuses, and says up front when a courier must approve):

Order status Change? How
placed / accepted (before Ready) ✅ freely no approval — re-quoted at today's prices; same shipper covers it → only the cost changes (pay / refund the difference); else the buyer picks a new option
ready, offers out, nobody accepted ✅ freely same; pending offers withdrawn, new ones sent
shipper accepted (incl. heading to the shop) ✅ with approval below — decline = that leg reassigned
picked up / on the way ✅ with approval below — decline = the original location stays
chain, some legs done ✅ with approval only the legs still to come are asked
delivered / collected / completed ❌ —
pickup order — "Deliver it instead" (§3.4) until collected

Limit: 3 location changes per order; after that only support (admin) can change it.

With approval. The buyer proposes a new pin; NexGate checks the affected shipper covers it and prices it from that shipper's table. The shipper sees old and new side by side (response window 30 min):

Shipper answers Result
Accept at the new cost the buyer pays the difference into that leg's escrow, or gets it back if cheaper
Accept at the old price (waives the increase) nothing more to pay
Decline — before pickup that shipper withdraws → the leg is reassigned (§10a: automatic if same / cheaper and not later, else the buyer decides)
Decline — after pickup the shipper cannot withdraw (never abandon a carried parcel) → the original destination stays

Sketch of the entity:

shipping_agreement     order, status, version
 ├ agreement_party     role (buyer / seller / shipper), who, leg, signed / declined / withdrawn + when
 ├ agreement_leg       from / to place, shipper, cost, ETA        ← each LEG escrow part points here
 └ agreement_change    type, proposed by, who must approve, deadline, default, status, before / after

5. Group purchase and installments

Group purchase

Installments

6. Shippers

6.1 Two kinds

Native (delivery business on NexGate) Integrated (external provider)
Set up by owner, in the app NexGate: one adapter + an admin row
Coverage / prices owner's tables the provider's API
Jobs offer in the app (required); SMS = notifications only NexGate calls their API
Status owner taps in the app their webhooks / polling, mapped to our statuses
Money owner's NexGate wallet a provider ledger account, settled by NexGate per contract / invoice
Delivery proof our codes their proof of delivery, else the buyer's "received" button
Chains can be any leg single leg only (whole trip, in one city)

Both answer the same contract: covers? · quotation (cost + ETA) · book · cancel · status — the engine never changes.

Shipper registry: native shippers register themselves (§6.2). Integrated providers are defined by the system (an adapter in code + one row created by NexGate) — never registered through the app; NexGate controls them fully (on / off, API keys, categories, limits, spend cap). Each integrated provider has its own ledger account and an admin status view (live rides, today's spend, balance owed, receipt differences, failed calls, webhook health). The engine and the admin shipper list treat both kinds the same way.

6.2 Native registration — two parts

Part 1 — KYC (POST /api/v1/shipping/businesses) — legal, checked once, auto-approved: business name · contact phone · office location (exactly one; pin screen like shops) · business licence (file + number + expiry; number unique) · director's NIDA copy (file + number) · LATRA licence (file + number + expiry). Documents are private (owner + admins). → status KYC_APPROVED (not live).

Part 2 — Service Setup (own endpoints, any time after KYC: .../{id}/setup/profile|hours|coverage|pricing|limits, GET .../{id}/setup = checklist): profile (logo, description, WhatsApp, email, vehicle badge) · service type (door and / or station) · working hours · coverage · pricing (station businesses: optional collection from shops — areas + fee, 0 = free) · limits (max value, accepts bulky + extra, response window, heads-up on/off).

Live: automatically once it has service type + coverage + pricing (hours default Mon–Sat 08:00–18:00). Statuses: KYC_APPROVED → LIVE ⇄ PAUSED (owner), SUSPENDED (admin / automatic). A user may own several. Needs two new File Thunder upload types: private business document, business logo.

6.3 Working hours (shared piece: businesses, shops, stations)

Several ranges per day · special days (holidays) · temporarily closed · same-day cut-off · EAT · overnight ranges allowed.

6.4 Shops: hours and pause

6.5 Integrated provider: Bolt (first and only one for now)

API reference in the repo: docs/shipping/providers/bolt/Bolt-Ride-Booker-API-Docs.pdf (Ride Booker API). Bolt confirmed the same API is used for parcels. The Bolt Business account is ready.

NexGate is a reseller of Bolt. The API is literally /reseller/v1/...: NexGate books rides with its business account, owns the customer (buyer and seller never deal with Bolt), Bolt bills NexGate monthly, and claims / refunds go NexGate → Bolt support (email) → credited on the monthly statement. To the buyer, Bolt is just one delivery option sold by NexGate.

Where Bolt is used

Mapping to the contract

Our question Bolt
Covers? estimations — boda category with an ETA; eta: null or AREA_NOT_SERVICED = no
Cost + ETA estimations → price {minimum_amount, maximum_amount}, eta
Book at Ready: estimate again → check the held price → POST rides (fare_id, valid 5 min, single use)
Cancel allowed until the ride has started
Status webhooks (live only, from Bolt's 3 fixed IPs, with our token) or polling ride details (≤ every 10 s)
Bolt state Our meaning
SEARCHING offer out
DRIVER_ON_ROUTE_TO_CLIENT accepted — rider coming to the shop
ARRIVED_AT_CLIENT rider at the shop
DRIVING_WITH_CLIENT picked up → on the way
COMPLETED delivered (Bolt's proof) → buyer confirms with the button
NO_DRIVER_FOUND / CANCELLED rejected → reassignment (another Bolt try or a native shipper)
back to SEARCHING after accepting, > ~10 min cancel the Bolt ride → reassignment
CLIENT_DID_NOT_SHOW (shop didn't hand over) seller pays Bolt's charge (from the items part at release); re-book on the next Ready

Price

On the ride

Control

6.6 The shipper app (native shippers)

Same NexGate app, in a "delivery business" mode (like managing a shop) — no separate rider app. For now only the owner uses it; team members (dispatcher / rider roles, assigning jobs, the rider's name shown to buyers) come later when businesses grow. Earnings always go to the owner's wallet.

Screen What it's for
Dashboard today's jobs, open offers, upcoming orders, earnings held / released, reliability, "Paused" banner
Upcoming orders in a paid agreement with this shipper, from payment, before any offer (below)
Offers job offers with a countdown: from / to on a map, parcel value band, bulky, cost, when the parcel reaches them (chains) → Accept / Reject (reason)
Heads-ups "order coming from Sinza in ~15 min" (non-binding)
Active jobs exact from / to (office, map, phone, hours), receiver, note, navigation, one button per next step
Codes and handovers show the pickup code to the seller; enter the buyer's delivery code; chain "handed over" / "received" + code; optional photo
Re-confirms "parcel now reaches you at 23:00 instead of 15:00 — still OK?"
History · Earnings · Reviews & reliability · Setup past timelines · held → released per job, wallet · ratings, replies, scores · KYC, Service Setup, pause / resume

Upcoming orders

Upcoming (5)
🕐 Kariakoo → Mikocheni · small · 7,000        Waiting for the seller to accept
📦 Sinza → Mbezi · bulky · 22,000              Seller is packing — offer expected soon
🚌 Leg 2: Magufuli → Mbeya Stand · 21,000      Parcel expected at your office tomorrow ~10:00

Endpoints (sketch) — also pushed live to the app, like chat:

GET  /api/v1/shipping/businesses/{id}/upcoming
GET  /api/v1/shipping/businesses/{id}/offers
POST /api/v1/shipping/offers/{offerId}/accept | /reject      (reason)
GET  /api/v1/shipping/businesses/{id}/jobs?status=active
POST /api/v1/shipping/jobs/{jobId}/status                    (next step)
POST /api/v1/shipping/jobs/{jobId}/handover                  (code + optional photo)
POST /api/v1/shipping/jobs/{jobId}/reconfirm
GET  /api/v1/shipping/businesses/{id}/earnings

6.7 Admin side and settings

Build order: the admin dashboard (screens) is the last thing built, after everything works. But the admin endpoints needed to fix stuck orders ship with the shipping service (no screens yet) — §6.7.2.

6.7.1 Where each setting lives

1 — Properties file: fixed platform rules (change = config + redeploy)

Setting Value
Meeting-point range 1 km
Loop guard (reassignments per order) 3
Re-confirm threshold for accepted legs 4 h
Chain safety net / buyer decision timeout 24 h / 24 h
Closed shipper: wait if it opens within 4 h
Seller accept window 24 opening hours
Pickup collection window (shop) / station + shipper-office hold 14 days / 7 days
Destination changes per order 3
Quotation price hold 5 days
Outlier rule / "expensive parcel" 3× / 500,000
Quotation options shown top 5
Codes: length / max wrong tries 4 digits / 5
Distance factor / rounding ×1.3 / up to the nearest 100
Estimation cache 1 h
Auto-pause: missed offers warn / pause 2 / 3
Auto-pause: suspend after auto-pauses 3 within 7 days
Acceptance rate warn / pause (last 20) 50% / 30%
Broke binding: suspend after / found at fault: suspend after 2 in 30 days / 2 in 30 days
False bulky claims → suspend 3
On-time warning (last 20 jobs) 60%
Grace period (rate rules) first 10 offers
Bulky mismatch: wasted-trip fee / auto-flag after 50% of the leg cost / 2 mismatches (different shippers)
Defaults shippers can override response window 30 min · station reach 30 km
Bolt price buffer 2% · category boda

2 — Per shipper, set by NexGate (the NexGate ↔ shipper agreement)

Setting Notes
Delivery commission % default = a new fee type in the effective-dated fee table (0% now); a shipper with its own deal gets an override with a start date (past orders keep the old rate)
Settlement terms (integrated) Bolt: monthly invoice
Daily spend limit (integrated) e.g. Bolt 2,000,000 / day
On / off (integrated) the kill-switch
Suspended / lifted (native) with a reason the shipper sees

3 — Per shipper, set by the shipper (Service Setup): hours, coverage, stations, prices, limits, heads-up on/off, its own response window, its own station reach.

4 — Admin-managed data: free-shipping campaigns, integrated provider records, review moderation, manual money actions.

6.7.2 Admin endpoints that ship WITH the shipping service (no screens)

SUPER_ADMIN only · every call needs a reason · every call is written to the audit log (who, what, when, why).

Endpoint (sketch) Why it's needed from day one
POST /api/v1/admin/shipping/escrows/{escrowId}/release · /refund stand-in for disputes: fix a stuck or reported order by hand
POST /api/v1/admin/shipping/orders/{orderId}/reassign · /cancel unstick a chain
POST /api/v1/admin/shipping/businesses/{id}/suspend · /lift stop a bad shipper
POST /api/v1/admin/shipping/providers/{code}/enable · /disable Bolt kill-switch
PUT /api/v1/admin/shipping/businesses/{id}/commission per-shipper commission override (with start date)

6.7.3 The dashboard (built last)

Area Contents
Native shippers list / search / filter; one shipper's page: profile, private KYC documents, coverage map, stations, prices, reliability, reviews, jobs, earnings; suspend / lift; hide review; documents expiring soon
Integrated providers kill-switch, spend limit, category, buffer; status view: live rides, today's spend vs limit, balance owed, receipt differences, failed calls, webhook health; settlement: record the monthly invoice, match the ledger, mark paid. API keys live in Vault, never in the database
Operations board stuck things: chains not fully accepted, buyer decisions waiting, money held a long time, problem reports, Bolt rides stuck searching — with the §6.7.2 actions and internal notes
Campaigns create / edit / pause / stop; budget used / reserved / left
Reports by ward / district / region only (never per person): deliveries, on-time rate, average cost, pickup vs delivery, shipper ranking, Bolt spend
Audit log every admin action

Who can do what (when the dashboard comes): STAFF_ADMIN — view everything, suspend / lift, hide reviews, notes, force reassignment. SUPER_ADMIN only — anything with money (release / refund, settlement), settings, Bolt kill-switch and limits, campaigns, commission overrides.

7. Coverage

7.1 One model for door and station businesses

  1. Where do you work? Tick areas from the region → district → ward list (with search). A read-only map shows the ticked areas to confirm. No radius, no drawing.
  2. Trips: WITHIN_EACH (both ends inside the same ticked area) or WITHIN_AND_ACROSS (both ends inside any ticked areas — crossing borders between them). Both ends must always be inside the ticked areas.
  3. Lines (optional, station businesses with separate lines): groups of areas; trips only between areas of the same line.

7.2 Stations (station businesses)

7.2a Handover points — where each leg picks up and drops off

  1. Leg 1 always starts with a collection at the shop (option A, decided 2026-10-13) — the seller never leaves the shop. Who collects:

    • A station business that collects from shops — it ticks the areas where it collects (same area picker) and sets a collection fee (flat; 0 = free). How it gets the parcel to its station is its own business; we don't model it. The collection is part of its leg: one leg, one business, one escrow part, the pickup code at the shop, "heading to the shop" applies. 
      Leg 1 🚌 Shabiby (collects free)  shop (Ubungo) → Mbeya Bus Stand   21,000   1 day
    • Otherwise a door shipper — the station route becomes a chain: door leg shop → station, then the station leg(s): 
      Leg 1 🚪 boda     shop (Ubungo) → Magufuli Terminal        3,500
Leg 2 🚌 Shabiby  Magufuli Terminal → Mbeya Bus Stand     21,000   → buyer collects, or leg 3 door
    • Neither → no station route from that shop (door-only options, else pickup only).

    The engine builds both kinds side by side; no special boost — free collection wins on cost by itself, and "fewer handovers" breaks ties when cost and arrival are equal. After launch (§16): the seller may drop at stations.

  2. Station businesses hand over only at their own stations (a bus company never drives to a door).

  3. Door businesses go wherever the leg needs, inside their coverage: the shop, a station, the buyer's door. Door shippers always come to the shop for leg 1 (the seller does not drop at a door shipper's office — after launch).

  4. The engine chooses which station: origin = a station a door shipper can reach from the shop (both inside that door shipper's coverage), nearest first; destination = its station nearest the buyer (within reach) and priced in its pair table; bus → bus offices within 1 km. Several stations in reach → each is a candidate; ranking picks; the others are alternatives in the quotation.

  5. Every leg in the agreement stores its exact from / to place (office name, pin, phone, hours), which is what that shipper's app shows ("Collect at: Shabiby office, Magufuli Terminal, gate 3 · [map] · open 06:00–20:00").

7.3 How the engine checks a trip

  1. Fast filter by area codes (no maps): both ends inside, trips rule, line rule.
  2. Stations (station businesses): origin station reached by a door leg from the shop (§7.2a), destination station nearest the buyer within reach.

7.4 Coverage request (sketch)

PUT /api/v1/shipping/businesses/{id}/setup/coverage
{ "areas": [ { "level": "REGION", "regionCode": "07" },
             { "level": "DISTRICT", "regionCode": "05", "districtCode": "03" },
             { "level": "WARD", "wardId": 1146 } ],
  "trips": "WITHIN_AND_ACROSS",
  "lines": [ { "name": "Line A", "areas": [0, 1, 2] } ],
  "stationReachKm": { "seller": 30, "buyer": 30 } }

Location helpers: region → district → ward lists + search; coverage outline for the map.

8. Pricing and ETA

8.1 Cost of one parcel

base (shipper's table) + value add-on (insurance) + bulky extra = cost

Base

Value add-on (optional ladder; fixed amounts per value range, % allowed for the top range) + max value accepted. Parcel value = the shop's items in the cart.

Bulky: new product field bulky (category can pre-tick); a parcel is bulky if any item is. Shipper: accepts bulky yes / no + extra. Non-accepting shippers are filtered out.

Rounding: whole TZS; add-ons rounded up to the nearest 100. New prices apply to new quotes only.

8.2 ETA

8.3 Fees

8.4 Bulky mismatch (product not ticked "bulky" but it is)

Rule: the seller pays (they set the flag), the buyer's price never changes, repeated mistakes fix the flag.

  1. Shipper reports at the shop, before pickup: "Can't carry — too big / heavy" (+ optional photo). Not possible after the pickup code is used.
  2. That leg is reassigned for bulky only: rejection reason BULKY_MISMATCH — not counted against the shipper's reliability; the parcel is now bulky → only bulky-accepting shippers, with their bulky extra.
  3. Money: the replacement's extra cost is paid by the seller automatically (taken from the items escrow at release). The buyer is not asked — just told "too big for a boda; a car is coming, no extra cost to you".
  4. Wasted trip: native first shipper gets 50% of its leg cost (properties setting), paid by the seller; Bolt → Bolt's cancellation charge, paid by the seller.
  5. Nobody can carry it: the buyer chooses pickup (delivery refunded) or cancel the whole order (full refund — seller's fault); the seller still pays the wasted trip.
  6. Fixing the flag: 1st mismatch → seller told to tick "bulky" (with the photo); 2nd mismatch on the same product from a different shipper → bulky set automatically; mismatches count in the seller's private reliability.
  7. Abuse: a shipper claiming mismatches on products others carry fine → flagged for admins.
  8. Opposite case (ticked bulky, actually small): no automatic change — higher prices are incentive enough.

8.5 Packing — the seller packs

9. Engine and ranking

  1. Where: both places' ward / district / region.
  2. Who: native coverage + integrated providers (skip a provider slower than ~2 s).
  3. Filter: coverage, max distance, max value, bulky, closed / cut-off (ETA shifts, not dropped), paused / suspended.
  4. Cost + ETA for each.
  5. Clean-up: hide dominated options (dearer and slower) and outliers (> 3× the cheapest of the same type) — "See all" shows them.
  6. Labels
    • 💰 Cheapest — ties → earlier arrival → reliability.
    • ⚡ Fastest — by the latest arrival of the range — ties → cheaper.
    • ⭐ Recommended — balance score; parcel > 500,000 → reliability-heavy; cheap parcel → price-heavy; else price + speed. At launch: price + time only (reliability added after launch).
    • One option may carry two labels.
  7. Order: labelled first (⭐ 💰 ⚡), then grouped "To your door" / "Collect at a station" by cost; top 5 + "See all".
  8. Fairness: new shippers get a neutral reliability + "New" badge; exact ties rotate.
  9. Quotations hold their prices 5 days (§4.1); the sheet pre-selects ⭐.

10. Job flow

  1. Seller accepts within 24 opening hours — else auto-cancel + full refund. Shipper gets a non-binding heads-up (switchable per shipper).
  2. Seller taps Packed / Ready → a confirm pop-up with two ticks, both required: ☐ "I have packed it well" · ☐ "The parcel label (QR) / number is on the package" (delivery only; pickup asks only the first). Recorded with the time — part of the evidence trail if a parcel arrives damaged or unlabelled. Then → pickup: buyer told; delivery: the offer goes to every leg at once, each showing when the parcel reaches them. The parcel does not move until all legs have accepted.
  3. Response window 30 min (per shipper), counted only while the shipper is open. Shipper closed at Ready → wait if it opens within ~4 h, else reassign.
  4. Accept = the shipper signs the agreement (§4.8) — capacity, not price (the price is the agreement). After accepting it is binding: the shipper must find a way — no buyer rescue mid-way; failing = heavy reliability hit, auto-pause, dispute / liability. Reject (reason) or timeout before accepting → reassignment (§10a).
  5. Who taps what: seller — accept, ready, verifies the pickup code; shipper — accept / reject, every status, submits the delivery code; buyer — gives the code (or the button), confirms "it's what I ordered".

10a. Reassignment (a shipper rejects or doesn't answer — before accepting)

Only before a shipper accepts; after accepting it is binding.

  1. Record: leg marked rejected (with reason) or timed out — a timeout counts exactly like a rejection. That shipper is excluded from this order and takes a reliability hit; 3 missed offers in a row → auto-pause.

  2. Replace that leg only. Other legs keep their acceptance; nothing moves until every leg has accepted. The replacement is the best-ranked option using the label the buyer chose (💰 → cheapest replacement …).

  3. Search in steps — stop at district:

    Step Replacement Neighbouring legs
    1. Nearby office within 1 km of the original handover points keep shipper + cost; get the updated exact office; no re-confirm
    2. Same district office in the same district as the original point door legs re-route inside their coverage and are re-costed; the total of the affected legs is compared; neighbours already accepted get a re-confirm ("drop at Ubungo Terminal instead, OK?")
    3. Beyond the district — no automatic swap buyer decides

    Door legs follow the same steps (first the same points, then a meeting point elsewhere in the district).

  4. Compare with the agreement (for the affected legs):

    • same or cheaper AND arriving no later (by latest arrival time) → automatic; the buyer is told; leg escrow re-pointed, difference refunded;
    • dearer / slower / nobody → the buyer decides while the parcel is still at the shop: pay the difference (top-up into the same leg escrow) · end the chain earlier (later legs refunded) · switch to pickup (all legs refunded) · cancel (everything refunded).

  5. The new shipper gets the offer (normal response window) — and may reject too (back to step 1).

  6. Loop guard: 3 reassignments per order (not per leg) → after that the buyer is always asked.

  7. Closed shipper at Ready: its window starts when it opens if that is within 4 h; otherwise reassign at once. 7a. Accepted legs whose time moves: moved by ≤ 4 h → an update, still bound; moved by > 4 h → re-confirm ("now 23:00 instead of 15:00, still OK?"); "no" → that leg is reassigned (counts toward the 3 per order). 7b. Chain safety net: not fully accepted 24 h after Ready → the buyer is asked: keep waiting · end the chain earlier · pickup · new delivery proposal · cancel the whole order. 7c. Buyer doesn't answer a decision screen: reminders, then after 24 h → automatic switch to pickup (leg escrows refunded; the buyer can still ask for a new delivery proposal).

  8. Free shipping: seller / campaign caps are recalculated for the new cost; the buyer pays only what's above them.

  9. The agreement keeps its history ("leg 3: Mbeya Riders rejected 10:42, busy → Mbeya Express 2,500").

  10. Who is told: buyer (notice on auto swaps / decision screen) · seller ("waiting for a courier", nothing to do) · legs already accepted ("still waiting for the full route", or a re-confirm when their point moved).

11. Codes and handovers

Parcel number — identifies the parcel (the codes below prove the handover):

Parcel number NX-4K7P-2Q 4-digit codes
Purpose identifies the parcel proves a handover
Secret? no — written on the box yes — hashed, never logged
How many one per parcel, for life one per handover

Codes

12. Money

12.1 Escrow parts per order

Buyer pays once → ORDER ESCROW
   ├ items part  → seller (fee: items + tax)
   └ leg part    → shipper owner (native) / provider ledger account (integrated)   ← one per leg
   (pickup = items part only)

"Held" = in escrow, nobody's yet. Release = to the payees. Refund = back to the buyer. Each part can be released or refunded on its own.

One escrow record per part, all children of the order:

Order ORD-…  (one shop's parcel)                                     ← parent
 ├ ESC-…101  part ITEMS  payee seller                    60,000  HELD
 ├ ESC-…102  part LEG    payee Kibuti Express   legId L1  3,500  HELD
 ├ ESC-…103  part LEG    payee Shabiby          legId L2 21,000  HELD
 └ ESC-…104  part LEG    payee Mbeya Riders     legId L3  2,500  HELD

12.2 When money moves

12.3 Adjustments and refunds

Event Money
Reassign — same / cheaper leg part re-pointed to the new shipper; difference refunded
Reassign — dearer buyer tops up the difference into the same leg part, or switches / cancels
Pickup → delivery new payment for the leg part(s)
Delivery → pickup / cancel the shipping, shipper not heading to the shop yet leg part(s) refunded
Cancel the shipping, shipper heading to the shop leg part refunded minus the wasted-trip fee (native 50% of the leg / Bolt's charge), which goes to the shipper
Destination change difference paid into / refunded from that leg part (nothing if the shipper keeps the old price)
Cancel before the seller accepts / pickup not collected in 14 days / seller cancels (§3.1) / group fails all parts refunded
Installment immediate / layaway legs with the down payment / a new payment at the end

The escrow table must allow a provider payee (today every escrow needs a user).

13. Free shipping

Seller-funded (shop setting): areas (same picker) · optional min order (this shop's items) · "I pay up to X per delivery" · product override (use shop / always free / never free). Mixed parcel: free only if every item qualifies.

NexGate campaigns (admin): areas · dates · min order · cap per delivery · audience (everyone / first order) · shops (all / selected) · total budget → stops automatically; budget reserved at payment.

Rules

14. Reviews, reliability, auto-pause

15. Open — to talk about next

# Topic Where we are
1 Buyer cancellation rule decided — see §3.4a
2 Buyer never confirms (all parts held) proposed: a check window after the delivery code; no decision
3 Disputes skipped for now (decided). Draft discussed: buyer / shipper / seller can open; reasons; evidence + automatic handover timeline; 48 h to respond; outcomes no fault / full / partial / return & refund / replacement; shipper liability capped at its leg part; one module for digital + physical
4 Failed delivery (buyer unreachable, refuses the parcel, return trip) with disputes
5 Auto-pause numbers decided — §14
8–12 Reassignment proposals decided — §10a items 4, 7a–7c; door shippers always come to the shop (§7.2a)
6 Cart: unsaved new pin decided — §4.4
7 Cart: default for a shop newly added decided — §4.4
13 Seller cancels a delivery order AFTER Ready open — before Ready is decided (§3.1); after Ready shippers have offers or signed (heading to the shop → who pays the wasted trip?)

15a. Future — decide after implementation

Parked on purpose (2026-10-12): build the main flows first, then decide these with real cases.

# Scenario What we know so far
F1 Buyer never confirms the delivery (never there to receive / never gives the code) idea: the shipper holds the parcel and it is returned to the shipper's office; how long, who pays storage / the trip back, what happens to the money — to decide
F1b Buyer received (code entered) but never taps "✓ It's what I ordered" all escrows stay held (no auto-release decided); a check window was proposed — to decide
F2 Failed delivery — buyer unreachable, refuses the parcel, wrong address "we will find a way later": re-attempt? return to the shop or the shipper's office? who pays?
F3 Parcel never collected at a station no rule yet (shop pickup has the 7-day rule); days to collect, storage, return — to decide
F4 Disputes, returns, shipper liability skipped for now — draft in §15 row 3

15b. Plan for the unhappy paths (recommended — NOT implemented now)

Based on common practice (Jumia, DHL-style couriers, Glovo, bus parcel services). Principle: whoever caused the failure pays for it. These are recommendations to confirm after the main flows are built.

F1 — Buyer not there to receive

  1. Rider calls the buyer and waits ~10 min, then marks "attempt failed" (time, location, optional photo). Buyer is notified: "We missed you — reschedule?"
  2. Up to 2 attempts; the buyer picks a new time for attempt 2 in the app.
  3. After the last failed attempt the parcel goes to the shipper's office and is held 7 days — the buyer can collect it there or ask for redelivery (pays a new delivery cost).
  4. Not collected in 7 days → returned to the seller. Buyer refunded items only; the delivery cost is kept by the shipper (work done) and the return trip is charged to the buyer.

F1b — Delivered (code entered) but the buyer never taps "✓ It's what I ordered"

F2 — Failed delivery

Cause Rule
Unreachable F1
Refused at the door, no reason back to the seller; buyer refunded items minus delivery + return
Refused because wrong / damaged (seen at the door) rider records reason + photo; back to the seller; buyer full refund; cost on the at-fault party (dispute)
Wrong / unclear address rider calls; corrected spot inside the shipper's coverage → deliver (buyer pays any difference); else F1

F3 — Parcel never collected at a station

Who pays

Failure caused by Pays
Buyer (absent, refused without reason, never collected) loses the delivery cost + pays the return; items refunded
Seller (wrong / damaged item seen at the door) both ways; buyer fully refunded
Shipper (lost, broken, gave up after accepting) its leg + liability (with disputes, later)

Plan — prepare now, switch on later

Phase What When
0 — data hooks (build WITH the shipping service) so the rules above slot in without rework: delivery attempt records (time, location, photo, outcome); failure reason codes (UNREACHABLE, REFUSED, REFUSED_DAMAGED, WRONG_ADDRESS, NOT_COLLECTED); statuses ATTEMPT_FAILED, HELD_AT_OFFICE, RETURNING, RETURNED; the held-at place on the fulfillment; timers stored as data (not code constants); the reverse direction allowed on a leg (A → B and B → A) now
1 — F1b auto-confirm the 3 / 7-day window + reminders (reuses the digital auto-confirm job) first, after launch — unblocks seller and shipper money
2 — attempts + office hold (F1, F2 unreachable) attempt button for riders, reschedule for buyers, 7-day hold, collect / redeliver next
3 — returns (F1 step 4, F2 refused, F3) reverse legs back to the seller, refunds minus costs, who-pays rules with or after disputes
4 — disputes (F4) the full draft in §15 later

16. To do after launch

17. Worked scenarios

Illustrative numbers. Each scenario uses only rules decided above.

A — Pickup, collected

Buyer in Sinza buys shoes from a shop in Ubungo, chooses Pickup.

Step Who What happens Money
1 Buyer pays 60,000 items escrow 60,000 HELD
2 Seller accepts, then taps Ready —
3 Buyer told "ready at Ubungo, Gate B" (directions, phone); picks "I'll come Thu 15:00" (optional) —
3a Seller sees "Buyer coming Thu 15:00"; buyer reminded Thursday morning —
4 Buyer + seller buyer shows code 4821, seller enters it → collected —
5 Buyer taps "✓ It's what I ordered" items released to seller (minus fee)

If the buyer never comes: reminders, then after 14 days auto-cancel → 60,000 refunded, stock back.

Instead Who What happens Money
Day 2, buyer phones: "I can't come, cancel" Seller Cancel → pop-up "I have already informed the buyer" → confirm 60,000 refunded, stock back
Before Ready, seller finds the shoes damaged, calls the buyer Seller same pop-up → confirm; fixes stock by hand 60,000 refunded

B — Door-to-door, one shipper

Phone 400,000, shop in Kariakoo → buyer's Home in Mikocheni (~9 km).

Step Who What happens Money
1 Buyer sheet shows quotation: 💰 Dar Cargo 7,000 · 1–2 h —
2 Buyer checkout → agreement; pays 407,000 items 400,000 + leg 7,000 HELD
3 Seller accepts (Dar Cargo gets a heads-up), packs, taps Ready —
4 Dar Cargo accepts the offer → receives pickup code —
5 Seller verifies the rider's pickup code, hands over → picked up —
6 Buyer told "on the way", receives delivery code 0937 —
7 Rider buyer tells the code, rider submits it → delivered —
8 Buyer opens, taps "✓ It's what I ordered" items → seller, 7,000 → Dar Cargo (one transaction)

C — Multi-shipper, door in another region

Laptop 1,500,000, shop at Mlimani City (Dar) → buyer's door in Mbeya.

Leg Shipper From → to Cost ETA
1 🚪 Kibuti Express shop → Shabiby office, Magufuli Terminal 3,500 2–3 h
2 🚌 Shabiby Magufuli → Shabiby office, Mbeya Stand 21,000 1 day
3 🚪 Mbeya Riders Mbeya Stand → buyer's door 2,500 1–2 h
Step What happens
Quotation buyer edits: none — or "collect at Mbeya Stand" removes leg 3 (−2,500)
Ready all three legs get the offer at once; parcel stays at the shop until all accept
Handovers shop → Kibuti (pickup code) · Kibuti → Shabiby ("handed over" / "received" + code) · Shabiby → Mbeya Riders (same) · Mbeya Riders → buyer (delivery code)
Release buyer taps "✓ It's what I ordered" → items + all 3 legs released together

D — Reassignment, nearby swap (automatic)

In C, Shabiby rejects ("full today").

Step Result
Search step 1 (1 km) Abood: offices 300 m (Magufuli) and 500 m (Mbeya Stand) from Shabiby's · 20,000 · 1 day
Compare cheaper, not slower → automatic
Money leg-2 escrow re-pointed to Abood; 1,000 refunded to the buyer
Others Kibuti and Mbeya Riders keep their leg and price; get the new exact office ("Abood office, gate 5"), no re-confirm
Buyer told "New courier for Dar → Mbeya: Abood, 1,000 refunded"

E — Reassignment, same district (re-confirm)

In C, no other bus company within 1 km at Magufuli; one leaves from Ubungo Terminal (same district).

Step Result
Search step 2 (district) Kilimanjaro Express from Ubungo · 21,500
Neighbours Kibuti re-routed shop → Ubungo Terminal, re-costed 3,000 (shorter)
Compare affected total 24,500 vs agreed 24,500 → same, not slower → automatic
Re-confirm Kibuti had already accepted and its drop point moved > 1 km → re-confirm "drop at Ubungo Terminal instead, OK?"
If Kibuti says no its leg is reassigned in turn (counts toward the 3 per order guard)

F — Chain fails → buyer chooses

In C, nobody in the district can do leg 2 at the agreed price; best is 30,000 (+9,000).

Buyer chooses Result
Pay the difference +9,000 from wallet into the leg-2 escrow; new shipper gets the offer
End the chain earlier e.g. collect in Dar — later legs refunded
Pickup all leg escrows refunded (27,000)
New delivery proposal new quotation → new agreement
Cancel the whole order full refund; stock back (allowed because the chain failed)

G — Switching

Case Allowed? Money
Ordered Pickup, seller already Ready, buyer taps "Deliver it instead" ✅ before collecting fresh quotation; pays delivery cost; offer goes to the shipper at once
Ordered Delivery, no shipper accepted yet, buyer switches to pickup ✅ legs refunded
Ordered Delivery, shipper accepted, not heading to the shop yet ✅ free legs refunded
Ordered Delivery, shipper heading to the shop ✅ with a fee leg refunded minus the wasted-trip fee
Ordered Delivery, parcel picked up ❌ only a destination change (scenario O)

H — Cancelling

When Allowed? Money
Before the seller accepts ✅ whole order full refund
Seller accepted, no shipper accepted ✅ shipping only (pickup / new proposal) legs refunded or adjusted
Shipper accepted, not heading to the shop ✅ shipping only, free legs refunded
Shipper heading to the shop ✅ shipping only Mbezi Boda leg 3,500 → buyer gets 1,750 back, Mbezi Boda gets 1,750
Parcel picked up ❌ shipping only a destination change
Chain failed ✅ shipping or the whole order as chosen

I — Free shipping, stacked

Shoes 60,000, shop in Kinondoni → buyer in Kinondoni (~4 km). Shop: free delivery in Kinondoni, pays up to 4,000. NexGate weekend campaign in Dar: pays up to 3,000.

Option Cost Seller pays NexGate pays Buyer pays
💰 Mbezi Boda (cheapest qualifying) 3,500 3,500 0 0 (Free)
⚡ Express Riders (faster) 5,000 3,500 0 1,500 (the difference — the discount is what the cheapest qualifying option costs)
a 9 km trip (other buyer) 7,500 4,000 3,000 500

Shipper always paid the full cost: leg escrow = buyer share + NexGate share (campaign account, at payment) + seller share (taken from the items escrow at release).

J — Group purchase

Case Result
Member pays (delivery 3,500) items + leg escrows HELD; price frozen even if the group fills days later
Group fails / member withdraws items + 3,500 refunded
Payment moved to another group fulfillment moves with it
Group fills, shipper rejects at Ready normal reassignment (D–F)

K — Installments

Mode Delivery
Immediate (ships after down payment) full delivery cost paid with the down payment
Layaway (ships after the last instalment) pickup / delivery chosen and paid after the last instalment
Agreement cancelled before shipping delivery cost refunded

L — Estimation on a card

Buyer's header address: Home, Kijitonyama. Product from a shop in Ubungo.

Shippers covering Card shows
Mbezi Boda 3,500 · 40–60 min, Dar Cargo 7,000 · 1–2 h 🚚 3,500 – 7,000 · Kijitonyama
one shipper, 5,000 🚚 5,000
free option + faster ones up to 2,000 🚚 Free – 2,000
none Pickup only at Ubungo

N — Bulky mismatch

Seller lists a 65" TV (value 1,800,000) without "bulky". Buyer chose 💰 Mbezi Boda 3,500.

Step What happens Money
Rider arrives at the shop taps "Can't carry — too big" + photo (before pickup) —
Reassignment (bulky only) Dar Cargo (car) 7,000 + bulky extra 15,000 = 22,000 buyer pays nothing more
Seller pays difference 22,000 − 3,500 = 18,500 + Mbezi Boda's wasted trip 1,750 (50%) taken from the items escrow at release
Buyer told "Too big for a boda — a car is coming, no extra cost to you" —
Product flag 1st mismatch → seller asked to tick bulky; if a 2nd shipper reports it on a later order → bulky set automatically —
Mbezi Boda reliability not affected gets 1,750

M — A shipper's day in the app (Mbezi Boda, owner only)

Time Screen What the owner sees / does Data visible
08:05 Upcoming new card "Sinza → Mbezi · small · 3,500 — Waiting for the seller to accept" (buyer just paid) areas only, size, value band, cost
08:40 Upcoming chip changes to "Seller is packing" + heads-up push "order coming from Sinza in ~15 min" areas only
09:00 Offers seller tapped Ready → offer with a 30-min countdown areas only, map of the two areas
09:04 Offers taps Accept → job moves to Active; pickup code 4821 shown full details now: shop Gate B + phone, buyer pin, directions "blue gate", receiver Mama Json +255712…
09:20 Active job at the shop: tells code 4821, seller verifies → taps Picked up —
09:45 Active job at the door: buyer says 0937 → enters it → Delivered —
11:30 Earnings job shows 3,500 held (waiting for the buyer's "✓ It's what I ordered") —
12:10 Earnings buyer confirmed → 3,500 released to the wallet (commission 0%) —
14:00 Offers another offer, but busy → Reject "too busy" → reliability notes it; order is reassigned —

O — Destination change (agreement change)

Buyer ordered shoes to home in Sinza with Mbezi Boda 3,500; at work in Mlimani City they change the destination.

Case Mbezi Boda answers Result
Before pickup, new cost 4,500 Accept at the new cost buyer pays +1,000 into the leg escrow
Before pickup, new cost 4,500 Accept at the old price nothing to pay
Before pickup Decline leg reassigned: Kibuti Express 4,000 is dearer → buyer decides (pay +500 / keep Sinza / pickup)
Before pickup no answer in 30 min Sinza stays; the buyer is told
After pickup, new cost 2,500 Accept buyer gets 1,000 back
After pickup Decline Sinza stays — the rider keeps the parcel and delivers as agreed
Delivered — not allowed

P — Cancelling the shipping (signed shipper)

Same order, Mbezi Boda signed (accepted) at 09:04.

When the buyer cancels the shipping Fee Money
09:10 — accepted, not set out none (like Bolt) 3,500 refunded; Mbezi Boda released, reliability unaffected
09:15 — Mbezi Boda tapped Heading to the shop wasted trip 50% 1,750 refunded to the buyer, 1,750 to Mbezi Boda
09:20 — picked up — not allowed; destination change only

# NexGate Shipping Service — Build Plan Development

How we build docs/shipping/SHIPPING_SERVICE_DESIGN.md (the "design", § numbers below point to it). Status: plan agreed to start, nothing built yet. Built on the Location Service (done: wards, shop locations, user addresses, frozen places).

Ground rules for every step

The order at a glance

Step Delivers Real-world result after the step
0 Foundations nothing visible; ground ready
1 Pickup, end to end (with codes and "✓ It's what I ordered") buyers can buy and collect at the shop
2 Native shipper registration (KYC + Service Setup basics) delivery businesses can sign up
3 Door coverage, pricing, ETA businesses describe where / how much
4 Engine: estimation + quotation (single door leg) buyers see real delivery costs
5 Cart / checkout / agreement, escrow per part buyers pay real delivery
6 Job flow: offers, codes, statuses, release first real door-to-door deliveries
7 Reassignment, switching, cancelling, bulky mismatch unhappy-but-common cases handled
8 Reliability, reviews, auto-pause, upcoming orders trust and planning
9 Stations (single leg) intercity: collect at a station
10 Multi-shipper chains shop → bus → door
11 Group purchase and installments shipping inside group / installment buys
12 Free shipping (seller rules + campaigns) "Free delivery" badges and filter
13 Bolt integration boda on demand in town
14 Admin dashboard (screens) ops tooling — last
later Notifications set · unhappy paths (§15a/b) · staging deploy after the build

Step 0 — Foundations

Goal: everything later steps stand on, with no behaviour change.

Check: existing checkout / orders / cart-escrow tests still pass; shop hours + pause visible; a code can be generated, verified, locked after 5 wrong tries, and never appears in logs.

Step 1 — Pickup, end to end

Goal: a buyer can buy, the seller prepares, the buyer collects with a code, money is released on confirmation.

Check: scenario A (§17) live: pay → accept → ready → code → collected → confirm → seller paid; 14-day expiry; seller cancel refunds; cancel before accept refunds; problem report freezes; admin release works and is logged.

Step 2 — Native shipper registration

Goal: a delivery business can sign up and get approved automatically.

Check: register with all documents → auto-approved; duplicate licence number refused; documents not visible to others; checklist shows what's missing; suspend / lift logged.

Step 3 — Door coverage, pricing, ETA

Goal: a business says where it works, how much, how long — and goes LIVE.

Check: the §7.1 crossing table (Sinza → Mikocheni with WITHIN_EACH vs ACROSS…) as tests; band and add-on maths incl. rounding; business flips to LIVE when complete.

Step 4 — Engine: estimation + quotation (single door leg)

Goal: buyers see real delivery options and costs.

Check: scenario L (cards) and the engine walk-throughs from the master guide (A, B, E) reproduce; cache hit on the second call; closed shipper shifts ETA instead of disappearing.

Step 5 — Cart, checkout, agreement, escrow per part

Goal: buyers pay the real delivery cost; money split into items + leg.

Check: scenario B up to payment: escrows created per part with the right payees and fees; quotation older than 5 days refreshed; edit at checkout re-quotes; ledger balance check passes.

Step 6 — Job flow, codes, delivery

Goal: the first real door-to-door delivery from offer to release.

Check: scenario B end to end; scenario M (a shipper's day) step by step; timeout counted; codes locked after 5 tries.

Step 7 — Reassignment, switching, cancelling, bulky mismatch

Goal: the common unhappy-but-normal cases.

Check: scenarios D, F, G, H, N, O, P; loop guard; silent buyer → pickup after 24 h; ledger balanced after every adjustment.

Step 8 — Reliability, reviews, auto-pause, upcoming orders

Check: the §14 trigger table as tests (2 / 3 missed, 3rd pause in 7 days → suspended…); new shipper not paused inside the grace period; upcoming card hides the exact pin until accepted.

Step 9 — Stations (reached by a door leg)

Check: a Mbeya → Morogoro trip as boda → bus (two legs) and as a bus company collecting free (one leg, ranked cheapest); no door shipper at the shop → no station route; pin within 1 km of a station offers "collect there"; empty pair = not offered.

Step 10 — Multi-shipper chains

Check: scenarios C, D, E with three legs; one leg rejecting while others accepted; re-confirm triggered by a

4 h move.

Step 11 — Group purchase and installments

Check: scenarios J and K.

Step 12 — Free shipping

Check: scenario I; campaign budget never overspent under parallel checkouts; refund returns budget.

Step 13 — Bolt integration

Check: sandbox flow (estimate → create → states → completed → receipt); NO_DRIVER_FOUND → reassignment; spend limit blocks new Bolt quotations; kill-switch hides Bolt immediately.

Step 14 — Admin dashboard (last)

Screens on top of the existing admin endpoints (§6.7.3): shippers + KYC documents, Bolt status and settlement, operations board, campaigns, reports (by area), audit log, STAFF_ADMIN / SUPER_ADMIN split.

After the build

Dependencies

0 ─► 1 ─► 2 ─► 3 ─► 4 ─► 5 ─► 6 ─► 7 ─► 8
                         │         ├─► 9 ─► 10
                         │         ├─► 11
                         │         ├─► 12
                         │         └─► 13
                         └─────────────────────► 14 (last)

Steps 9, 11, 12, 13 can be reordered after step 6 (each only needs the single-leg flow). 10 needs 9.