Ammendments

Amended Endpoints — what the feed release changes in endpoints you already have

Author: Josh S. Sakweli, Backend Lead Team
Last Updated: 2026-09-18
Version: v1.0 (backend branch fet/feed_baking)

Base URL: https://dev.api.nexgate.co (staging) · https://api.nexgate.co (production)

Short Description: This document lists only the endpoints that already existed and have now changed. Nothing here is a new URL. Every path below is one your app already calls today, and every entry says exactly what moved under it, whether the change is visible in the response, and whether you have to do anything about it.

Its sibling document is 09_NEW_ENDPOINTS.md — the endpoints and controllers that did not exist before (home feed, reels, marketplace, events, interactions, and the admin/ops APIs). If a path is not in this file, it was not amended; if it is not in that file, it is not new.

Hints:

How to read this document

Each entry carries two chips.

Change type — what kind of amendment it is:

Chip Meaning
SECURITY FIX The endpoint used to return content the viewer was not allowed to see
RESPONSE A field was added, or a field that used to be empty is now filled
BEHAVIOUR Same shape, different contents, ordering or side effect
PARAMS A query parameter is now validated or clamped
BEING DELETED Still answers today, but is scheduled for removal — do not build on it

App action — what the frontend must do:

Chip Meaning
🟢 None Ships safely with no app change
🟡 Optional Works untouched, but there is something worth picking up
🔴 Required The app must handle this or it will misbehave

Index

# Endpoint Change type App action
1 GET /api/v1/e-social/feed RESPONSE · BEING DELETED 🔴 Required
2 GET /api/v1/e-social/clip/feed SECURITY FIX · RESPONSE · BEHAVIOUR 🔴 Required
3 GET /api/v1/e-social/clip/{mediaId} SECURITY FIX · RESPONSE 🟡 Optional
4 GET /api/v1/e-social/clip/user/{userId}/videos SECURITY FIX · RESPONSE · BEHAVIOUR 🔴 Required
5 POST /api/v1/e-social/clip/{mediaId}/view BEHAVIOUR 🟡 Optional
6 GET /api/v1/e-social/hashtags/{hashtag}/posts SECURITY FIX · PARAMS · BEHAVIOUR · RESPONSE 🟢 None
7 GET /api/v1/e-social/hashtags/trending BEHAVIOUR · PARAMS 🟢 None
8 GET /api/v1/e-social/hashtags/search BEHAVIOUR · PARAMS 🟢 None

Standard Response Format

Unchanged. Every endpoint below still answers in the usual envelope:

{
  "success": true,
  "httpStatus": "OK",
  "message": "Operation completed successfully",
  "action_time": "2026-09-18T10:30:45",
  "data": { }
}

Errors are unchanged too: 400 bad request, 401 token problems, 403 permission, 404 not found, 422 validation, 500 server. Where an amendment introduces a new reason for an existing status, the entry says so.

Endpoints

1. Home feed (old)

Endpoint: GET /api/v1/e-social/feed

Change type: RESPONSE BEING DELETED · App action: 🔴 Required — move to /api/v1/feed/home

This endpoint is going away. It is listed here because it still answers today and its contents changed. Do not build anything new on it.

Access Level: 🔒 Protected · Authentication: Authorization: Bearer <access token>

What changed

a) topComments is now always populated.

This endpoint used to call the post mapper with "no top comments", so topComments came back empty on every post. The mapper now always fills it (up to 5, most-liked first) because the feed needs it and loading it costs nothing extra in the batched mapper.

b) A backend switch can make it answer from the new pipeline. There is a feed.legacy.fromPipeline setting that makes this endpoint serve the new feed in the old shape. It was built for a migration that is no longer needed, and it is not part of the plan — it will be deleted together with the endpoint. Mentioned only so nobody is surprised to find it in the code.

Response shape (unchanged)

{
  "success": true,
  "httpStatus": "OK",
  "message": "Feed retrieved",
  "action_time": "2026-09-18T10:30:45",
  "data": {
    "posts": [ { "postId": "…", "topComments": [ { } ] } ],
    "unseenCount": 12,
    "nextCursor": "eyJ0IjoxNzU4…"
  }
}

What the app must do

Move to GET /api/v1/feed/home. See 09_NEW_ENDPOINTS.md A1 and 07_FEED_ENDPOINTS_GUIDE.md. This path is deleted once you have.

Until then it keeps working as it does today.

2. Clip feed

Endpoint: GET /api/v1/e-social/clip/feed

Change type: SECURITY FIX RESPONSE BEHAVIOUR · App action: 🔴 Required

Access Level: 🔒 Protected · Authentication: Authorization: Bearer <access token>

What changed

a) It no longer leaks private videos. The feed used to return clips from followers-only and mentions-only posts to anyone, and clips from accounts the viewer had blocked. It now filters by the post's visibility, the viewer's follow relationship, mentions, and blocks — in the database, before paging.

b) Moderation labels apply. A clip whose post or author carries a moderation label is either dropped from the page or marked for an interstitial, per the rules in 01_ARCHITECTURE.md §9.2. Followers are treated more leniently than strangers.

c) Two new fields in each clip (see the table below).

d) A page can be shorter than limit while hasMore is still true. The cursor is taken from the last row the database returned, before labels remove anything. So clips.length < limit no longer means "end of feed" — only hasMore === false and nextCursor === null mean that.

e) limit is clamped to 1–20 (it was previously used as given).

Query Parameters

Parameter Type Required Description Validation Default
cursor string No Opaque page cursor from the previous response Invalid cursor → 400 none (first page)
limit integer No Clips per page Clamped to 1–20 (new) 10

New response fields

Field Type Values Description
visibility string ALLOW, INTERSTITIAL INTERSTITIAL means: do not autoplay. Show a "sensitive content — tap to view" cover first. Defaults to ALLOW
media.durationMs integer milliseconds Clip length. Useful for the progress bar, and needed to report watch time correctly in the interactions batch

Success Response JSON Sample

{
  "success": true,
  "httpStatus": "OK",
  "message": "Clip feed fetched",
  "action_time": "2026-09-18T10:30:45",
  "data": {
    "clips": [
      {
        "postId": "4f2a77e1-0c8b-4d2f-9a11-7b6c3e5d8f90",
        "visibility": "ALLOW",
        "media": {
          "id": "9b1c2d3e-4f5a-6b7c-8d9e-0f1a2b3c4d5e",
          "durationMs": 14200,
          "variants": { "hls": "https://…/master.m3u8", "thumb": "https://…/thumb.jpg" }
        },
        "engagement": { },
        "userInteraction": { }
      }
    ],
    "nextCursor": "MjAyNi0wOS0xN1QxMDoyMjozMTo0ZjJh…",
    "hasMore": true
  }
}

What the app must do

  1. Stop using clips.length < limit as the end-of-feed test. Use hasMore.
  2. Honour visibility. INTERSTITIAL clips must not autoplay behind no cover.
  3. Expect fewer clips than before for some viewers. That is correct, not a regression.

3. Single clip

Endpoint: GET /api/v1/e-social/clip/{mediaId}

Change type: SECURITY FIX RESPONSE · App action: 🟡 Optional

Access Level: 🔒 Protected · Authentication: Authorization: Bearer <access token>

What changed

Error Response JSON Sample

{
  "success": false,
  "httpStatus": "NOT_FOUND",
  "message": "Clip not found",
  "action_time": "2026-09-18T10:30:45",
  "data": "Clip not found"
}

What the app should do

Treat 404 here as "this clip is gone or not for you" and return the user to the previous screen — it is no longer safe to assume a 404 means deleted.

4. A user's videos

Endpoint: GET /api/v1/e-social/clip/user/{userId}/videos

Change type: SECURITY FIX RESPONSE BEHAVIOUR · App action: 🔴 Required

Access Level: 🔒 Protected · Authentication: Authorization: Bearer <access token>

What changed

Exactly the same three things as the clip feed (entry 2), on a profile's video grid:

What the app must do

Use hasMore, not the page length, to decide whether to load more in the profile grid.

5. Record a clip view

Endpoint: POST /api/v1/e-social/clip/{mediaId}/view

Change type: BEHAVIOUR · App action: 🟡 Optional

Access Level: 🔒 Protected · Authentication: Authorization: Bearer <access token>

Response: still 204 No Content, still no body. The request contract has not changed.

What changed

What the app should do

Keep calling this for the view counter, and send watch time as a VIEW event with watchMs and mediaDurationMs to POST /api/v1/feed/interactions/batch. Anything sent in this body is thrown away.

6. Posts for a hashtag

Endpoint: GET /api/v1/e-social/hashtags/{hashtag}/posts

Change type: SECURITY FIX PARAMS BEHAVIOUR RESPONSE · App action: 🟢 None

Access Level: 🌐 Public (a signed-in viewer sees more) · Authentication: optional bearer token

What changed

a) It no longer leaks private posts. The old version loaded every post id carrying the tag into memory and checked only "published and not deleted" — so followers-only and mentions-only posts reached anyone who opened the tag page. Visibility, mentions and blocks are now enforced in the database query itself.

b) Paging is real. The whole tag is no longer loaded into memory; the page and its total count are computed in the database.

c) Ordering is by published_at descending (it was createdAt). For a scheduled post these differ: the post now sorts by when it went live, which is what a reader expects.

d) page and size are clamped instead of being trusted.

e) topComments is now populated on each post, for the same reason as entry 1.

f) Hashtags are matched in any script. Tags are normalised the same way at write and read time, so non-Latin tags (Swahili, Arabic, CJK …) now match instead of silently returning nothing.

Query Parameters

Parameter Type Required Description Validation Default
filter enum No ALL, PRODUCTS, SHOPS, EVENTS unknown value → 400 ALL
page integer No 1-based page number Below 1 is treated as 1 (new) 1
size integer No Posts per page Clamped to 1–50 (new) 20

What the app should do

Nothing. Expect a signed-out viewer to see fewer posts than a signed-in one, and a blocked author's posts never to appear.

Endpoint: GET /api/v1/e-social/hashtags/trending

Change type: BEHAVIOUR PARAMS · App action: 🟢 None

Access Level: 🌐 Public · Authentication: none

Response shape: unchanged — a list of { hashtag, posts }.

What changed

b) Private and draft posts never count. Only public, published, non-deleted posts inside the window — so a private post can no longer push its tag onto a public page.

c) Results are cached for 5 minutes per window. The page is public and read far more often than it changes.

Query Parameters

Parameter Type Required Description Validation Default
window string No 24h, 7d, 30d. Anything else is treated as 24h — 24h
limit integer No How many tags Clamped to 1–50 (new) 15

8. Hashtag suggestions (type-ahead)

Endpoint: GET /api/v1/e-social/hashtags/search

Change type: BEHAVIOUR PARAMS · App action: 🟢 None

Access Level: 🌐 Public · Authentication: none

Response shape: unchanged — a list of { hashtag, posts }.

What changed

Query Parameters

Parameter Type Required Description Validation Default
q string Yes What the user has typed so far Blank → empty list —
limit integer No How many suggestions Clamped to 1–20 (new) 5

Old endpoints being deleted

There is no migration and no grace period. This is a staging platform with no production users and no data worth keeping — the database will be dropped. So these paths are not being "migrated away from" over time; they are deleted from the codebase in one commit, as soon as the frontend confirms it has switched.

What that means for you:

The strings below are literal — copy them into your project search to find every call site.

Search for this What it is Replace with Notes
api/v1/e-social/feed Old home feed api/v1/feed/home Response shapes differ — see 09 A1
api/v1/e-social/feed/stream Feed SSE stream nothing — use api/v1/events The chat/events stream now carries a feed.new hint; on receiving it, call api/v1/feed/home/has-new
api/v1/e-social/feed/heartbeat SSE keep-alive nothing Dies with the stream above
api/v1/e-social/clip/feed Clip feed api/v1/feed/reels Still amended in the meantime (entry 2), so it behaves correctly right up to the day it goes

Not going anywhere — keep calling these: api/v1/e-social/clip/{mediaId}, api/v1/e-social/clip/{mediaId}/view, api/v1/e-social/clip/user/{userId}/videos, and all three api/v1/e-social/hashtags/… endpoints.

A one-liner for a frontend repo:

grep -rn "e-social/feed\|e-social/clip/feed" src/ --include=*.{ts,tsx,js,jsx,dart,kt,swift}

Every hit is a call site that must move. When that grep returns nothing, tell the backend team — that is the signal to delete.

What did not change

Worth stating plainly, so nobody goes looking:

Doc What it covers
09_NEW_ENDPOINTS.md Every new endpoint and new controller
07_FEED_ENDPOINTS_GUIDE.md The app team's walkthrough of the new feed screens
05_INTERACTIONS_CLIENT_GUIDE.md What the app must report back, and exact action definitions
01_ARCHITECTURE.md The design. §A.3 is the migration and the deletion list; §9.2 is the label rule

New Endpoints — everything the feed release adds

Author: Josh S. Sakweli, Backend Lead Team
Last Updated: 2026-09-18
Version: v1.0 (backend branch fet/feed_baking)

Base URL: https://dev.api.nexgate.co (staging) · https://api.nexgate.co (production)

Short Description: Every endpoint here is new — a new URL on a new controller. Nothing in this document replaces a field or changes an existing response. It is in two parts: Part A is what the apps call (the five feed surfaces and the interactions endpoint), Part B is what the admin panel and the operations team call (sponsored slots, business rules, moderation labels, interest mapping, backfills and the per-account debug trace).

Its sibling document is 08_AMENDED_ENDPOINTS.md — the endpoints you already have that changed behaviour. If a path is in this file it did not exist before; if it is in that file it is not new.

Hints:

How this document is organised

Part Who calls it Controllers
🅰️ Part A — App-facing Android, iOS, web HomeFeedController, ReelsFeedController, MarketFeedController, EventsFeedController, FeedListsController, InteractionController
🅱️ Part B — Admin & operations Admin panel, ops PromotionAdminController, LabelAdminController, InterestAdminController, FeedBackfillController

Each entry carries an access chip:

Chip Meaning
🔒 User Any signed-in account
🛡️ Admin ROLE_SUPER_ADMIN or ROLE_STAFF_ADMIN
🛡️ Super admin ROLE_SUPER_ADMIN only

Index

Part A — App-facing

# Endpoint Purpose Replaces
A1 GET /api/v1/feed/home The home feed: posts and products api/v1/e-social/feed
A2 GET /api/v1/feed/home/has-new The "new posts" bubble the feed SSE stream
A3 GET /api/v1/feed/reels The reels feed api/v1/e-social/clip/feed
A4 GET /api/v1/feed/marketplace Marketplace "For You" —
A5 GET /api/v1/feed/events Events "For You" —
A6 GET /api/v1/feed/products/{productId}/similar "Similar items" on a product page —
A7 GET /api/v1/feed/shops/suggested "Shops you might like" —
A8 POST /api/v1/feed/interactions/batch Report what the user did —

Part B — Admin & operations

# Endpoint Purpose Role
B1 POST /api/admin/feed/sponsored Start a sponsored campaign Admin
B2 GET /api/admin/feed/sponsored List active campaigns Admin
B3 DELETE /api/admin/feed/sponsored/{id} Stop a campaign Admin
B4 POST /api/admin/feed/business-rules Boost or suppress something for a period Admin
B5 GET /api/admin/feed/business-rules List running and upcoming rules Admin
B6 DELETE /api/admin/feed/business-rules/{id} End a rule now Admin
B7 GET /api/admin/feed/debug/{accountId} Why this person saw this feed Admin
B8 POST /api/admin/feed/labels Label a post, product, shop or account Admin
B9 DELETE /api/admin/feed/labels/{labelId} Remove a label Admin
B10 GET /api/admin/feed/labels Labels on one target, with history Admin
B11 GET /api/admin/feed/interests The interest list and every mapping Admin
B12 GET /api/admin/feed/interests/unmapped What still needs mapping Admin
B13 PUT /api/admin/feed/interests/product-categories/{categoryId} Map a product category Admin
B14 PUT /api/admin/feed/interests/event-categories/{categoryId} Map an event category Admin
B15 PUT /api/admin/feed/interests/hashtags/{hashtag} Map a hashtag Admin
B16 POST /api/admin/feed/backfills Republish existing data into the feed Super admin
B17 GET /api/admin/feed/backfills Recent backfill runs Super admin
B18 POST /api/admin/feed/backfills/{runId}/cancel Stop a run Super admin

Standard Response Format

Same envelope as the rest of the platform.

{
  "success": true,
  "httpStatus": "OK",
  "message": "Home feed",
  "action_time": "2026-09-18T10:30:45",
  "data": { }
}

{
  "success": false,
  "httpStatus": "NOT_FOUND",
  "message": "No active campaign 42",
  "action_time": "2026-09-18T10:30:45",
  "data": "No active campaign 42"
}

Errors used in this document: 400 bad request (a rule or campaign that makes no sense, an unknown label, an unknown backfill aggregate), 401 missing/expired token, 403 wrong role, 404 not found (unknown id, unknown surface, no debug trace), 422 validation failure with a field map, 500 server error.

Part A — App-facing

The shared feed contract

A4, A5, A1 and A3 all answer with the same three things:

Field Type Description
feedSessionId string The session this page came from. Send it back in every interaction as context.feedSessionId — it is how a like is tied to the feed that showed the item
items array The items, already in display order
nextCursor string | null Pass it as cursor for the next page. null = nothing more right now

And every item carries:

Field Type Description
position integer The item's place in the feed, from 0. Send it back as context.position
source string Why this item is here. Send it back as context.source
visibility string ALLOW, or INTERSTITIAL → show a "sensitive content, tap to view" cover before the media

source values: FOLLOWING, CELEBRITY, RECO, INTEREST, FALLBACK, SPONSORED, TRENDING, SEARCH. Do not invent others — the interactions endpoint rejects unknown ones.

A1. Home feed

Purpose: The main feed. Mixes posts from people the user follows, recommended posts, and products.

Endpoint: GET /api/v1/feed/home

Access: 🔒 User · Authentication: Authorization: Bearer <access token>

Replaces: api/v1/e-social/feed

Query Parameters

Parameter Type Required Description Validation Default
cursor string No Cursor from the previous page. Omit for the first page, and omit on pull-to-refresh to start a new session opaque none
limit integer No Items per page clamped to 1–30 15

Success Response JSON Sample

{
  "success": true,
  "httpStatus": "OK",
  "message": "Home feed",
  "action_time": "2026-09-18T10:30:45",
  "data": {
    "feedSessionId": "fs-77aa31c8",
    "items": [
      {
        "type": "POST",
        "position": 0,
        "source": "FOLLOWING",
        "visibility": "ALLOW",
        "post": { "postId": "4f2a77e1-0c8b-4d2f-9a11-7b6c3e5d8f90" },
        "product": null
      },
      {
        "type": "PRODUCT",
        "position": 1,
        "source": "RECO",
        "visibility": "ALLOW",
        "post": null,
        "product": { "productId": "8c31a0d2-77e4-4b1a-9f3c-2d5e6a7b8c90" }
      }
    ],
    "nextCursor": "eyJzIjoiZnMtNzdhYTMxYzgiLCJwIjoxNX0"
  }
}

Success Response Fields

Field Description
items[].type POST or PRODUCT. Exactly one of post / product is filled; the other is null
items[].post A full PostResponse — the same object the rest of the API returns for a post
items[].product A ProductSummaryResponse — the same object the marketplace list returns

Notes

A2. New posts available ("the bubble")

Purpose: Tells the app whether to show the "N new posts" bubble at the top of the home feed.

Endpoint: GET /api/v1/feed/home/has-new

Access: 🔒 User · Authentication: Authorization: Bearer <access token>

Replaces: the old feed SSE stream (api/v1/e-social/feed/stream)

Query Parameters

Parameter Type Required Description Validation
since integer Yes publishedAt of the newest post the app is currently showing, as epoch milliseconds must parse as a long

Success Response JSON Sample

{
  "success": true,
  "httpStatus": "OK",
  "message": "New posts",
  "action_time": "2026-09-18T10:30:45",
  "data": {
    "count": 7,
    "more": false,
    "authors": [
      { "accountId": "…", "userName": "mariam", "profileMedia": { } }
    ],
    "nextPollIn": 300
  }
}

Success Response Fields

Field Description
count How many new posts, capped at 20
more true when there were more than 20 — show "20+"
authors Up to 3 authors, for the avatars on the bubble
nextPollIn Seconds to wait before asking again. Read this from the response, do not hard-code it — the server lengthens it under load, with no app release

When to call it

Moment Action
Feed comes on screen Call once
Feed stays on screen Call again after nextPollIn seconds
A feed.new event arrives on the /api/v1/events stream Call immediately
count > 0 and the user has scrolled down Show the bubble
count > 0 and the user is already at the top No bubble — fetch and insert the posts
Bubble tapped Call GET /api/v1/feed/home with no cursor and prepend the result above the existing list

The feed.new event. The existing chat/events stream now carries an event named feed.new with an empty body on the account's personal channel. It carries no posts and no count — it only means "call has-new now". It is throttled to at most one a minute, and it is an optimisation: if the stream is down, the next poll finds the posts anyway.

A3. Reels feed

Purpose: The vertical clip feed.

Endpoint: GET /api/v1/feed/reels

Access: 🔒 User · Authentication: Authorization: Bearer <access token>

Replaces: api/v1/e-social/clip/feed

Query Parameters

Parameter Type Required Description Validation Default
cursor string No Cursor from the previous page opaque none
limit integer No Clips per page clamped to 1–30 10

Success Response JSON Sample

{
  "success": true,
  "httpStatus": "OK",
  "message": "Reels",
  "action_time": "2026-09-18T10:30:45",
  "data": {
    "feedSessionId": "fs-91bd4410",
    "items": [
      {
        "position": 0,
        "source": "RECO",
        "clip": {
          "postId": "…",
          "visibility": "ALLOW",
          "media": { "id": "…", "durationMs": 14200, "variants": { "hls": "https://…/master.m3u8" } }
        }
      }
    ],
    "nextCursor": "eyJzIjoiZnMtOTFiZDQ0MTAiLCJwIjoxMH0"
  }
}

Notes

A4. Marketplace "For You"

Purpose: A personalised product feed for the marketplace tab.

Endpoint: GET /api/v1/feed/marketplace

Access: 🔒 User · Authentication: Authorization: Bearer <access token>

Query Parameters

Parameter Type Required Description Validation Default
cursor string No Cursor from the previous page opaque none
limit integer No Products per page clamped to 1–30 20

Success Response JSON Sample

{
  "success": true,
  "httpStatus": "OK",
  "message": "Marketplace for you",
  "action_time": "2026-09-18T10:30:45",
  "data": {
    "feedSessionId": "fs-2210ab7e",
    "items": [
      { "position": 0, "source": "RECO", "visibility": "ALLOW", "product": { "productId": "…" } },
      { "position": 1, "source": "SPONSORED", "visibility": "ALLOW", "product": { "productId": "…" } }
    ],
    "nextCursor": null
  }
}

source here means: RECO (the model), FOLLOWING (a shop the user subscribes to), SPONSORED (a paid slot — label it in the UI), FALLBACK (trending, new shops, or products seen in posts).

A5. Events "For You"

Purpose: Event discovery.

Endpoint: GET /api/v1/feed/events

Access: 🔒 User · Authentication: Authorization: Bearer <access token>

Query Parameters

Parameter Type Required Description Validation Default
cursor string No Cursor from the previous page opaque none
limit integer No Events per page clamped to 1–30 20

Success Response JSON Sample

{
  "success": true,
  "httpStatus": "OK",
  "message": "Events for you",
  "action_time": "2026-09-18T10:30:45",
  "data": {
    "feedSessionId": "fs-55c0d913",
    "items": [
      { "position": 0, "source": "FOLLOWING", "visibility": "ALLOW", "event": { "eventId": "…" } }
    ],
    "nextCursor": "eyJzIjoiZnMtNTVjMGQ5MTMiLCJwIjoyMH0"
  }
}

source here means: RECO, FOLLOWING (an organiser the user follows), FALLBACK (upcoming events, by bookings). event is the usual EventSummaryResponse.

A6. Similar items

Purpose: The "Similar items" strip on a product page.

Endpoint: GET /api/v1/feed/products/{productId}/similar

Access: 🔒 User · Authentication: Authorization: Bearer <access token>

Path Parameters

Parameter Type Required Description
productId UUID Yes The product being viewed

Query Parameters

Parameter Type Required Description Validation Default
limit integer No How many products clamped to 1–50 20

Success Response JSON Sample

{
  "success": true,
  "httpStatus": "OK",
  "message": "Similar items",
  "action_time": "2026-09-18T10:30:45",
  "data": {
    "items": [
      { "source": "RECO", "visibility": "ALLOW", "product": { "productId": "…" } },
      { "source": "CATEGORY", "visibility": "ALLOW", "product": { "productId": "…" } }
    ]
  }
}

No paging and no feedSessionId — this is a strip, not a feed. source is RECO (the model's similar items) or CATEGORY (best sellers of the same category, used when the model has nothing).

A7. Suggested shops

Purpose: The "Shops you might like" strip.

Endpoint: GET /api/v1/feed/shops/suggested

Access: 🔒 User · Authentication: Authorization: Bearer <access token>

Query Parameters

Parameter Type Required Description Validation Default
limit integer No How many shops clamped to 1–30 10

Success Response JSON Sample

{
  "success": true,
  "httpStatus": "OK",
  "message": "Suggested shops",
  "action_time": "2026-09-18T10:30:45",
  "data": {
    "items": [
      {
        "source": "NEW",
        "shopId": "…",
        "shopName": "Kilimanjaro Coffee",
        "shopSlug": "kilimanjaro-coffee",
        "shopDescription": "Single-origin roasters",
        "logo": { },
        "isVerified": true,
        "city": "Arusha",
        "region": "Arusha",
        "subscriberCount": 1284
      }
    ]
  }
}

source: RECO, NEW (opened in the last 30 days) or POPULAR (most subscribers). No contact details are returned — the viewer does not follow this shop yet.

A8. Report interactions

Purpose: Send what the user did, in batches. This is the only way the recommendation model learns.

Endpoint: POST /api/v1/feed/interactions/batch

Access: 🔒 User · Authentication: Authorization: Bearer <access token>

Success status: 202 Accepted

Full definitions of every action live in 05_INTERACTIONS_CLIENT_GUIDE.md. That document is the contract; this entry is the reference. What your batch becomes once the backend has it is 10_EVENT_CATALOGUE.md §5.

This is the only endpoint on the whole platform that puts anything on the event stream from the app. Everything else the model learns — posts, products, shops, events, profiles, follows, blocks, orders, wishlists, and even likes and purchases — is published automatically from committed database rows. The app never announces that something exists or changed; it only reports what it alone can see: impressions, views, watch time, skips, clicks and searches.

Request JSON Sample

{
  "sessionId": "s-8812e0c4",
  "client": { "platform": "ANDROID", "appVersion": "2.4.1", "networkType": "CELLULAR" },
  "events": [
    {
      "clientEventId": "c-000184",
      "action": "IMPRESSION",
      "targetType": "POST",
      "targetId": "4f2a77e1-0c8b-4d2f-9a11-7b6c3e5d8f90",
      "occurredAt": "2026-09-18T10:22:31.900Z",
      "context": { "surface": "REELS", "position": 3, "feedSessionId": "fs-77aa", "source": "RECO" }
    },
    {
      "clientEventId": "c-000185",
      "action": "VIEW",
      "targetType": "POST",
      "targetId": "4f2a77e1-0c8b-4d2f-9a11-7b6c3e5d8f90",
      "occurredAt": "2026-09-18T10:22:41.100Z",
      "watchMs": 9000,
      "mediaDurationMs": 6000,
      "loopCount": 1,
      "soundOn": true,
      "mediaIndex": 0,
      "context": { "surface": "REELS", "position": 3, "feedSessionId": "fs-77aa", "source": "RECO" }
    }
  ]
}

Request Body Parameters

Parameter Type Required Description Validation
sessionId string No The app session —
client.platform string No ANDROID, IOS, WEB enum
client.appVersion string No e.g. 2.4.1 —
client.networkType string No WIFI, CELLULAR, OFFLINE, UNKNOWN enum
events array Yes The batch max 100 per request
events[].clientEventId string Yes Your own id, unique within the batch max 64 chars
events[].action string Yes See the action table below enum
events[].targetType string Yes* POST, PRODUCT, SHOP, EVENT, PROFILE *not required for SEARCH
events[].targetId string Yes* UUID of the target must be a UUID
events[].occurredAt string Yes When it happened, on the device ISO 8601
events[].dwellMs / watchMs integer No Time on screen / watched 0 – 6 h
events[].mediaDurationMs integer No Length of the media 0 – 12 h
events[].loopCount integer No Replays 0 – 1000
events[].soundOn boolean No Was sound on —
events[].mediaIndex integer No Which item of a carousel 0 – 100
events[].context.surface string No FEED, REELS, SEARCH, PRODUCT_PAGE, SHOP_PAGE, EVENT_PAGE, PROFILE_PAGE, RECOMMENDATION, NOTIFICATION, CHAT enum
events[].context.position integer No The item's position in the feed —
events[].context.feedSessionId string No From the feed response —
events[].context.source string No From the item enum
events[].context.viaPostId string No The post a product was reached through UUID
events[].context.query string No The search text, for SEARCH —

Unknown fields are ignored, deliberately: a newer app adding a field must never lose the batch.

Actions the app sends

IMPRESSION, VIEW, SKIP, CLICK, SEARCH, NOT_INTERESTED, HIDE.

Actions the app must NOT send

LIKE, UNLIKE, SHARE, BOOKMARK, COMMENT, ADD_TO_CART, REMOVE_FROM_CART, PURCHASE, BLOCK, REPORT, MUTE_AUTHOR.

The backend sends these itself when the change commits, so an app that also sent them would count every like twice. They come back rejected with SENT_BY_SERVER. Call the normal feature API (the like endpoint, the cart endpoint) and the interaction is recorded for you.

Success Response JSON Sample

{
  "success": true,
  "httpStatus": "ACCEPTED",
  "message": "Interactions received",
  "action_time": "2026-09-18T10:30:45",
  "data": { "accepted": 2, "dropped": 0, "rejected": [] }
}
Field Description
accepted Kept
dropped Valid but not kept (rate limit, or the event log was briefly unavailable). Do not resend — these are signal, not records
rejected Invalid. Do not resend. Each entry is { clientEventId, reason } — a rejection is a bug in the app; log it in debug builds

Rejection reasons

CLIENT_EVENT_ID_REQUIRED_MAX_64, UNKNOWN_ACTION, SENT_BY_SERVER, UNKNOWN_TARGET_TYPE, TARGET_ID_NOT_UUID, DUPLICATE_CLIENT_EVENT_ID, OCCURRED_AT_NOT_ISO_8601, DURATION_OUT_OF_RANGE, LOOP_COUNT_OUT_OF_RANGE, MEDIA_INDEX_OUT_OF_RANGE, UNKNOWN_SURFACE, UNKNOWN_SOURCE, POSITION_OUT_OF_RANGE, VIA_POST_ID_NOT_UUID, BATCH_LIMIT_100, EMPTY_EVENT.

Part B — Admin & operations

Everything below is on /api/admin/feed. A signed-in account without the role gets 403.

Sponsored campaigns

A sponsored campaign places one product at fixed slots in home and marketplace sessions, while it is inside its window. A viewer sees the same campaign at most feed.sponsored.capPerDay times in 24 hours (a feed_params setting), so a campaign cannot follow someone down the page.

Campaigns and rules are re-read from the database at most every 60 seconds, so a change can take up to a minute to show up in feeds.

Not built yet: billing, budgets and self-serve. A campaign today is created by staff and runs between two dates, free.

B1. Start a campaign

Endpoint: POST /api/admin/feed/sponsored · Access: 🛡️ Admin

Request JSON Sample

{
  "productId": "8c31a0d2-77e4-4b1a-9f3c-2d5e6a7b8c90",
  "startsAt": "2026-10-01T00:00:00Z",
  "endsAt": "2026-10-15T00:00:00Z"
}
Parameter Type Required Validation
productId UUID Yes the product must exist, else 400 Product not found
startsAt ISO 8601 instant Yes —
endsAt ISO 8601 instant Yes must be after startsAt, else 400 endsAt must be after startsAt

Success Response

{
  "success": true, "httpStatus": "OK", "message": "Campaign added",
  "action_time": "2026-09-18T10:30:45",
  "data": { "id": 42, "productId": "8c31a0d2-…", "startsAt": "2026-10-01T00:00:00Z", "endsAt": "2026-10-15T00:00:00Z", "active": false }
}

active is true only while the campaign is inside its window.

B2. List campaigns

Endpoint: GET /api/admin/feed/sponsored · Access: 🛡️ Admin

Returns an array of the object above — running and upcoming campaigns.

B3. Stop a campaign

Endpoint: DELETE /api/admin/feed/sponsored/{id} · Access: 🛡️ Admin

Parameter Type Required Description
id integer Yes The campaign id from B1/B2

Ends it immediately. An id that is not an active campaign gives 404 No active campaign {id}.

Business rules

A business rule multiplies the feed score of everything matching it, for a period. It is the lever for "push this category this week" or "quieten this shop while we investigate" — without touching code. Several matching rules multiply together, and like campaigns they are re-read at most every 60 seconds.

B4. Add a rule

Endpoint: POST /api/admin/feed/business-rules · Access: 🛡️ Admin

Request JSON Sample

{
  "matchType": "CATEGORY",
  "matchValue": "b81d9a34-5f2c-4c7e-9a10-3e5d7f9b1c22",
  "multiplier": 1.4,
  "startsAt": "2026-10-01T00:00:00Z",
  "endsAt": "2026-10-08T00:00:00Z"
}
Parameter Type Required Description Validation
matchType string Yes PRODUCT, SHOP, CATEGORY (all three match products) or ACCOUNT (matches posts by, and events organised by, that account) enum
matchValue string Yes The id of that product / shop / category / account 36-character UUID
multiplier number Yes Above 1 boosts, below 1 suppresses 0.1 – 3.0
startsAt ISO 8601 instant Yes — —
endsAt ISO 8601 instant Yes — must be after startsAt

Success Response

{
  "success": true, "httpStatus": "OK", "message": "Rule added",
  "action_time": "2026-09-18T10:30:45",
  "data": { "id": 17, "matchType": "CATEGORY", "matchValue": "b81d9a34-…", "multiplier": 1.4,
            "startsAt": "2026-10-01T00:00:00Z", "endsAt": "2026-10-08T00:00:00Z" }
}

B5. List rules

Endpoint: GET /api/admin/feed/business-rules · Access: 🛡️ Admin

Running and upcoming rules, as an array of the object above. Expired rules are not listed.

B6. End a rule now

Endpoint: DELETE /api/admin/feed/business-rules/{id} · Access: 🛡️ Admin

404 No running or upcoming rule {id} if it has already finished.

B7. Why did this person see this feed?

Purpose: The per-account debug trace. For support and for tuning: it shows every item the last feed build produced, and every item it threw away and why.

Endpoint: GET /api/admin/feed/debug/{accountId} · Access: 🛡️ Admin

Path & Query Parameters

Parameter Type Required Description Default
accountId UUID Yes Whose feed —
surface string No HOME, REELS, MARKET, EVENTS HOME

How to switch it on

Tracing is off unless the account is listed. Add the account id to the feed.debug.accounts row in the feed_params table, then have that person (or a test account) open the feed. The trace is kept for 1 hour.

Success Response JSON Sample

{
  "success": true, "httpStatus": "OK", "message": "Last session trace",
  "action_time": "2026-09-18T10:30:45",
  "data": {
    "surface": "HOME",
    "builtAt": 1789412345678,
    "shown": [
      {
        "position": 0, "type": "POST", "id": "4f2a77e1-…", "source": "FOLLOWING",
        "baseScore": 1.81, "score": 2.35, "visibility": "ALLOW",
        "trace": ["NewShopBoost x1.3"]
      }
    ],
    "removed": [ { "type": "POST", "id": "9b10…", "source": "FALLBACK", "filter": "Seen" } ]
  }
}

Errors

Status When
404 Unknown surface {x} surface is not one of the four
404 No trace: add the account to feed_params 'feed.debug.accounts', then open that feed (kept 1 h) Tracing was off, or the trace expired

Moderation labels

A label is a moderation outcome attached to a post, product, shop or account. The feed reads labels; it has no special cases of its own. Labels do not delete anything — they decide who stops seeing it.

The rule (first match wins, and strangers are treated more strictly than followers, because following was the user's choice and discovery is ours):

Label Viewer follows the author Viewer does not follow
suspended (account or item), prohibited_item removed removed
counterfeit_suspected shown removed
spam_suspected (account) shown removed
reported_threshold shown removed
low_quality_media shown removed
sensitive_media shown behind a cover (INTERSTITIAL) removed

reported_threshold is applied automatically when a post passes the report threshold. The rest are applied by staff, by a rule, or by a model.

B8. Add a label

Endpoint: POST /api/admin/feed/labels · Access: 🛡️ Admin

Request JSON Sample

{
  "targetType": "POST",
  "targetId": "4f2a77e1-0c8b-4d2f-9a11-7b6c3e5d8f90",
  "label": "sensitive_media",
  "expiresInHours": 72
}
Parameter Type Required Description Validation
targetType string Yes POST, PRODUCT, SHOP, ACCOUNT else 400 Unknown target type
targetId UUID Yes What to label —
label string Yes suspended, spam_suspected, counterfeit_suspected, sensitive_media, prohibited_item, reported_threshold, low_quality_media else 400 Unknown label '…'
expiresInHours integer No Omit for a permanent label must be positive

B9. Remove a label

Endpoint: DELETE /api/admin/feed/labels/{labelId} · Access: 🛡️ Admin

404 if that label id does not exist.

B10. Labels on one target

Endpoint: GET /api/admin/feed/labels?targetType={type}&targetId={id} · Access: 🛡️ Admin

Success Response JSON Sample

{
  "success": true, "httpStatus": "OK", "message": "Labels",
  "action_time": "2026-09-18T10:30:45",
  "data": {
    "targetType": "POST",
    "targetId": "4f2a77e1-…",
    "active": ["sensitive_media"],
    "history": [
      {
        "id": 91, "label": "sensitive_media", "source": "MANUAL", "created_by": "…",
        "created_at": "2026-09-18T09:00:00Z", "expires_at": "2026-09-21T09:00:00Z", "removed_at": null
      }
    ]
  }
}

active is what is in force now; history includes removed and expired labels, so a decision can be explained later. source is MANUAL, RULE, REPORT_THRESHOLD or MODEL.

Interest mapping

Interests are the shared language between social, marketplace and events: one person has one interest profile, and a like on a post can move what they see in the shop. For that to work, every product category, event category and popular hashtag must be mapped to interests.

⚠️ This mapping is not finished. Use B12 to see what is still missing. Until a category is mapped, its items reach people only through follows, trending and fallbacks — not through interests.

B11. The interest list and all mappings

Endpoint: GET /api/admin/feed/interests · Access: 🛡️ Admin

{
  "success": true, "httpStatus": "OK", "message": "Interest mappings",
  "action_time": "2026-09-18T10:30:45",
  "data": {
    "interests": [ { "id": "…", "name": "Fashion" } ],
    "productCategories": [ { "key": "b81d9a34-…", "name": "Sneakers", "interestIds": ["…"] } ],
    "eventCategories":   [ { "key": "…", "name": "Live music", "interestIds": ["…"] } ],
    "hashtags":          [ { "key": "mitumba", "name": "#mitumba", "interestIds": ["…"] } ]
  }
}

For a hashtag, key is the tag without the #.

B12. What still needs mapping

Endpoint: GET /api/admin/feed/interests/unmapped · Access: 🛡️ Admin

{
  "success": true, "httpStatus": "OK", "message": "Still to map",
  "action_time": "2026-09-18T10:30:45",
  "data": {
    "productCategories": [ { "id": "…", "name": "Sneakers" } ],
    "eventCategories":   [ { "id": "…", "name": "Workshops" } ],
    "hashtags":          [ { "hashtag": "mitumba", "posts": 812 } ]
  }
}

A product category counts as mapped when a parent category is mapped. Hashtags listed are the most used unmapped tags on public posts of the last 30 days — the ones worth mapping first.

B13–B15. Map a category or hashtag

Endpoints: PUT /api/admin/feed/interests/product-categories/{categoryId} · /event-categories/{categoryId} · /hashtags/{hashtag} · Access: 🛡️ Admin

Request JSON Sample

{ "interestIds": ["a1b2c3d4-…", "e5f6a7b8-…"] }
Parameter Type Required Description Validation
interestIds array of UUID Yes Replaces the whole mapping for that key. An empty array removes the mapping at most 5; every id must exist, else 404 Unknown interest id in […]

For /hashtags/{hashtag}, pass the tag with or without # — it is normalised. A value that is not a usable tag gives 404 Not a hashtag: …. An unknown category id gives 404 … not found: {id}.

Backfills

A backfill republishes data that already exists into the feed's event log — used when a new field is added, after an incident, or when a topic is rebuilt from scratch. Existing rows are read and re-sent; nothing is modified.

B16. Start a backfill

Endpoint: POST /api/admin/feed/backfills · Access: 🛡️ Super admin

Request JSON Sample

{ "aggregate": "product" }
Parameter Type Required Description Validation
aggregate string Yes post, follow, block, product, shop, event, profile, order, wishlist, or all else 400 Unknown aggregate '…'

Only one run per aggregate at a time. Asking again while one is pending or running returns that existing run instead of starting a second.

B17. Recent runs

Endpoint: GET /api/admin/feed/backfills · Access: 🛡️ Super admin

{
  "success": true, "httpStatus": "OK", "message": "Backfill runs",
  "action_time": "2026-09-18T10:30:45",
  "data": [
    {
      "id": 7, "aggregate": "product", "status": "RUNNING", "lastKey": "8c31a0d2-…",
      "keysDone": 18400, "keysFailed": 0, "requestedBy": "…",
      "createdAt": "2026-09-18T10:00:00Z", "startedAt": "2026-09-18T10:00:02Z",
      "finishedAt": null, "error": null
    }
  ]
}
Field Description
status PENDING, RUNNING, DONE, CANCELLED, FAILED
lastKey Where it has reached — a cancelled or failed run resumes from here rather than starting over
keysDone / keysFailed Progress
error Why it failed, when it did

B18. Cancel a run

Endpoint: POST /api/admin/feed/backfills/{runId}/cancel · Access: 🛡️ Super admin

Stops the run at its current key. 404 if that run id does not exist.

Doc What it covers
08_AMENDED_ENDPOINTS.md Existing endpoints that changed, and the old endpoints being deleted
07_FEED_ENDPOINTS_GUIDE.md The app team's walkthrough: paging, the bubble, failure behaviour, switch checklist
05_INTERACTIONS_CLIENT_GUIDE.md Exact definition of every interaction the app sends
06_RECOMMENDATION_DEVELOPER_GUIDE.md For the AI developer: topics, and the lists the feed reads back
01_ARCHITECTURE.md The design behind all of it

Sending interactions — guide for the app team

Audience: Android, iOS and web developers. Status: built on the backend (branch fet/feed_baking, 2026-09-17).

The recommendation model learns from what people do. It can only learn from what the app sends, and anything not sent today is lost for good: a watch time nobody recorded cannot be recovered later. Please send everything below from the first release that has the endpoint.

The same action must mean the same thing on every platform. A VIEW on Android and a VIEW on iOS are counted together; if their definitions differ, the model learns the difference between the apps instead of what people like.

1. The endpoint

POST /api/v1/feed/interactions/batch
Authorization: Bearer <access token>
Content-Type: application/json

{
  "sessionId": "s-8812e0c4",
  "client": { "platform": "ANDROID", "appVersion": "2.4.1", "networkType": "CELLULAR" },
  "events": [
    { "clientEventId": "c-000184", "action": "IMPRESSION", "targetType": "POST", "targetId": "4f2a77e1-0c8b-4d2f-9a11-7b6c3e5d8f90",
      "occurredAt": "2026-09-17T10:22:31.900Z",
      "context": { "surface": "REELS", "position": 3, "feedSessionId": "fs-77aa", "source": "RECO" } },
    { "clientEventId": "c-000185", "action": "VIEW", "targetType": "POST", "targetId": "4f2a77e1-0c8b-4d2f-9a11-7b6c3e5d8f90",
      "occurredAt": "2026-09-17T10:22:41.100Z",
      "watchMs": 9000, "mediaDurationMs": 6000, "loopCount": 1, "soundOn": true, "mediaIndex": 0,
      "context": { "surface": "REELS", "position": 3, "feedSessionId": "fs-77aa", "source": "RECO" } }
  ]
}

Answer: 202

{ "data": { "accepted": 2, "dropped": 0, "rejected": [] } }

2. When to send

Rule Value
Send every 10 seconds
…or as soon as the buffer holds 50 events
…and always when the app goes to the background
Maximum per request 100 events (extra events are rejected with BATCH_LIMIT_100)
Offline keep up to 500 unsent events on disk; beyond that drop the oldest
Rate limit 600 events per minute per account; normal use never reaches it

Never send one request per event.

3. Fields

Batch

Field Required Notes
sessionId recommended A new id each time the app comes to the foreground after ≥ 30 min away. ≤ 64 characters
client.platform recommended ANDROID, IOS, WEB
client.appVersion recommended e.g. 2.4.1
client.networkType recommended WIFI, CELLULAR, OFFLINE, UNKNOWN. A clip abandoned on a slow connection means something different from one skipped on wifi

Event

Field Required Notes
clientEventId yes Unique per event on this device, ≤ 64 characters. A counter or a UUID. Reuse it when resending the same event
action yes See §4
targetType yes, except SEARCH POST, PRODUCT, SHOP, EVENT, PROFILE. A reel is a POST
targetId yes, except SEARCH The item's UUID
occurredAt recommended When it happened on the device, ISO-8601 UTC (2026-09-17T10:22:31.900Z). Omitted → the time the server received it. More than 24 h old or more than 5 min ahead is pulled into that window
dwellMs for VIEW of images, products, events, shops, profiles Time the item was on screen (≥ 50 % visible)
watchMs for VIEW / SKIP of video Total time actually played, including repeats. 9 s on a 6 s clip that looped once is 9000
mediaDurationMs for video The clip's length
loopCount for video How many times it restarted from the beginning
soundOn for video Whether sound was on while playing
mediaIndex for carousels Which item (0-based) of a post with several images or videos
context.surface recommended FEED, REELS, SEARCH, PRODUCT_PAGE, SHOP_PAGE, EVENT_PAGE, PROFILE_PAGE, RECOMMENDATION, NOTIFICATION, CHAT
context.position recommended in lists 0-based rank on screen. Without it the model cannot tell a tap earned by relevance from a tap earned by being first
context.feedSessionId when the item came from the feed The feed page's session id (the feed API will return it)
context.source when the item came from the feed FOLLOWING, CELEBRITY, RECO, INTEREST, FALLBACK, SPONSORED, TRENDING, SEARCH, as returned by the feed API
context.viaPostId when acting on something attached to a post The post's id, e.g. tapping a product tagged in a post
context.query for SEARCH What was searched; trimmed, cut at 200 characters

Send numbers as whole milliseconds. Leave a field out rather than sending 0 when it was not measured.

4. Actions — exact definitions

Action Send when Carries
IMPRESSION The item is ≥ 50 % visible for ≥ 300 ms. Once per item per feed session, however often it scrolls back into view context
VIEW Image, product, event, shop, profile: ≥ 50 % visible for ≥ 1 s. Video: played ≥ 2 s. Send once, when the item leaves the screen, with the total time dwellMs or watchMs/mediaDurationMs/loopCount/soundOn, mediaIndex
SKIP A video was scrolled away less than 1 s after it started watchMs, mediaDurationMs
CLICK The detail page, shop or profile was opened from the item context
SEARCH A query was submitted context.query, no target
NOT_INTERESTED "Show fewer like this"
HIDE "Hide this"

Do not send LIKE, UNLIKE, COMMENT, BOOKMARK, SHARE, ADD_TO_CART, REMOVE_FROM_CART, PURCHASE, BLOCK, REPORT or MUTE_AUTHOR. Just call the feature's own API (like a post, add to cart, pay). The backend sends the interaction itself once the change is saved, so it is counted exactly once, even if the app crashes before its next batch, and never for a like that failed. The batch API rejects these actions with SENT_BY_SERVER.

What the backend cannot know is where the tap happened. Keep sending CLICK with context (surface, position, source, viaPostId) when a product, event or profile is opened; that is how the model learns a post led to a purchase.

Clips (reels)

Worked examples

A reel watched to the end and replayed partly, sound on, on cellular VIEW, watchMs: 9000, mediaDurationMs: 6000, loopCount: 1, soundOn: true, surface REELS.

A reel flicked past IMPRESSION (if it met 50 % / 300 ms), then SKIP with watchMs: 400, mediaDurationMs: 15000.

Third image of a carousel post looked at for 2.5 s VIEW, targetType: POST, mediaIndex: 2, dwellMs: 2500.

A product tagged in a post, opened then added to cart CLICK, targetType: PRODUCT, context.viaPostId = the post. The add to cart itself is sent by the backend.

Search SEARCH, context: { surface: "SEARCH", query: "running shoes" }; then an IMPRESSION per result with surface: SEARCH and its position.

5. Rejection reasons

Reason Meaning
CLIENT_EVENT_ID_REQUIRED_MAX_64 Missing or too long
UNKNOWN_ACTION Not in §4
SENT_BY_SERVER An action the backend already sends (like, comment, cart, purchase, …); call the feature API only
UNKNOWN_TARGET_TYPE / TARGET_ID_NOT_UUID Target missing or malformed
DUPLICATE_CLIENT_EVENT_ID Same clientEventId twice in one batch
OCCURRED_AT_NOT_ISO_8601 Unparseable time
DURATION_OUT_OF_RANGE A duration below 0 or above 6 h (12 h for mediaDurationMs)
LOOP_COUNT_OUT_OF_RANGE / MEDIA_INDEX_OUT_OF_RANGE Out of 0–1000 / 0–100
UNKNOWN_SURFACE / UNKNOWN_SOURCE / POSITION_OUT_OF_RANGE / VIA_POST_ID_NOT_UUID Context fields malformed
BATCH_LIMIT_100 More than 100 events in one request
EMPTY_EVENT A null in the list

A rejection is a bug in the app. Log it in development builds.