Private Chat & Calls Phase 2
Production Architecture
NexGate / QBIT SPARK | Version 1.0 Ejabberd · WebRTC Calls · Voice & Video · MessagePack · Coturn · Message Interactions
Table of Contents
- NexGate Chat Roadmap
- What Is Phase 2
- What We Are Building
- Full Architecture
- Ejabberd — The Transport Backbone
- Ejabberd ↔ Spring Boot Bridge
- Authentication Flow
- Message Flow — Phase 2
- Voice Calls
- Video Calls
- Coturn — TURN Relay
- MessagePack Encoding
- Broadcast Channels
- MQTT — Mini Apps Foundation
- Message Interactions
- Docker Deployment
- Database Schema
- Commerce Stanzas & Custom Namespaces
- Build Order
1. NexGate Chat Roadmap
Before any code is written — understand the full journey. Three stages. Each builds on the previous.
Stage 1 — Local Experiments (Terminal Only, No Coding)
Goal: understand the tools before building with them
Duration: 1 week
Output: confidence, not code
Method: terminal only — Docker CLI, curl, sendxmpp
NO Android app
NO Android Studio
NO Java project
NO NexGate codebase
Everything in this stage is throwaway
Run it locally on your Xubuntu machine
No production VPS involved
Tools to Install First
# XMPP CLI client
sudo apt install sendxmpp
# WebSocket CLI client
wget https://github.com/vi/websocat/releases/download/v1.12.0/websocat.x86_64-unknown-linux-musl
chmod +x websocat.x86_64-unknown-linux-musl
sudo mv websocat.x86_64-unknown-linux-musl /usr/local/bin/websocat
# STUN test client
sudo apt install stuntman-client
# Network packet inspection
sudo apt install tcpdump
# Python + MessagePack (for experiment 7)
pip3 install msgpack --break-system-packages
# curl and docker — already installed ✅
Experiment 1 — Ejabberd Running Locally
Goal: get Ejabberd running, send one message via terminal
Success: message delivered, logs confirm routing
# Start Ejabberd
docker run -d \
--name ejabberd \
-p 5222:5222 \
-p 5280:5280 \
-p 5285:5285 \
ghcr.io/processone/ejabberd
# Wait for startup
sleep 15
# Check it's running
docker exec ejabberd ejabberdctl status
# Expected: Node ejabberd@localhost is started
# Create two test users
docker exec ejabberd ejabberdctl register alice nexgate.com password123
docker exec ejabberd ejabberdctl register bob nexgate.com password123
# Verify users exist
docker exec ejabberd ejabberdctl registered_users nexgate.com
# Expected output:
# alice
# bob
# Send message alice → bob (no app needed!)
docker exec ejabberd ejabberdctl send_message \
chat alice@nexgate.com bob@nexgate.com \
"" "Habari Bob! Kutoka terminal"
# Watch Ejabberd logs — see message routing
docker logs ejabberd --tail 30
# Open dashboard in browser
# http://localhost:5280/admin
# admin / password (default)
# See users, sessions, statistics
What you learn:
How Ejabberd starts and configures
ejabberdctl is your management CLI
Messages route without any app
Dashboard shows what's happening
Logs show every routing decision
Experiment 2 — REST API (How Spring Boot Will Talk to Ejabberd)
Goal: talk to Ejabberd via HTTP — same way Spring Boot will
Success: curl commands work, responses received
# Send message via REST API (this is exactly what Spring Boot does)
curl -s -X POST http://localhost:5285/api/send_message \
-H "Content-Type: application/json" \
-d '{
"from": "alice@nexgate.com",
"to": "bob@nexgate.com",
"body": "Kutoka curl — kama Spring Boot!"
}' | python3 -m json.tool
# Get all connected users
curl -s -X POST http://localhost:5285/api/connected_users \
-H "Content-Type: application/json" \
-d '{}' | python3 -m json.tool
# Get registered users
curl -s -X POST http://localhost:5285/api/registered_users \
-H "Content-Type: application/json" \
-d '{"host": "nexgate.com"}' | python3 -m json.tool
# Create a MUC group chat room
curl -s -X POST http://localhost:5285/api/create_room \
-H "Content-Type: application/json" \
-d '{
"name": "nexgate-test-room",
"service": "conference.nexgate.com",
"host": "nexgate.com"
}' | python3 -m json.tool
# List active MUC rooms
curl -s -X POST http://localhost:5285/api/muc_online_rooms \
-H "Content-Type: application/json" \
-d '{"service": "conference.nexgate.com"}' | python3 -m json.tool
# Kick a user session
curl -s -X POST http://localhost:5285/api/kick_session \
-H "Content-Type: application/json" \
-d '{
"user": "alice",
"host": "nexgate.com",
"resource": "test",
"reason": "Test kick"
}' | python3 -m json.tool
What you learn:
Every curl call = what Spring Boot RestTemplate does
REST API is how NexGate backend controls Ejabberd
Port 5285 = admin API (internal only in production)
All operations possible without any mobile app
Experiment 3 — sendxmpp (Connect as XMPP User)
Goal: connect as a real XMPP user from terminal
Success: send/receive messages between two terminal sessions
# Terminal 1 — send message as alice
echo "Habari Bob! Ninatuma kutoka terminal" | sendxmpp \
--username alice \
--password password123 \
--host localhost \
--port 5222 \
--domain nexgate.com \
--tls-ca-path /dev/null \
--insecure \
bob@nexgate.com
# Watch Ejabberd logs in another terminal:
docker logs ejabberd -f
# See stanzas flowing in logs:
# Received message from alice@nexgate.com
# Routing to bob@nexgate.com
# Delivered ✅
# Send typing indicator (composing stanza)
# sendxmpp handles this via --chat-state flag
echo "Ninaandika..." | sendxmpp \
--username alice \
--password password123 \
--host localhost \
--port 5222 \
--domain nexgate.com \
--insecure \
--chat-state \
bob@nexgate.com
What you learn:
XMPP login flow from client perspective
Stanza routing in Ejabberd logs
How typing indicators flow
What mobile app will do — terminal does it first
Experiment 4 — Watch Raw XMPP Stanzas
Goal: see actual XML stanzas flowing over the wire
Success: raw XMPP XML visible in terminal
# Terminal 1 — watch all XMPP traffic
sudo tcpdump -i lo -A port 5222 2>/dev/null | grep -A5 "<message\|<presence\|<iq"
# Terminal 2 — connect via websocat (WebSocket)
websocat ws://localhost:5280/ws
# Type this in websocat terminal:
# (open XMPP stream)
# Terminal 3 — send message via sendxmpp
echo "Test stanza" | sendxmpp \
--username alice \
--password password123 \
--host localhost \
--domain nexgate.com \
--insecure \
bob@nexgate.com
# Watch Terminal 1 — see raw XML:
# <message from='alice@nexgate.com'
# to='bob@nexgate.com'
# type='chat'>
# <body>Test stanza</body>
# </message>
What you learn:
What XMPP stanzas actually look like on wire
Difference between connection, auth, message stanzas
How namespaces appear in real traffic
Visual confirmation of everything in the docs
Experiment 5 — Spring Boot Auth Bridge
Goal: Ejabberd calls Spring Boot to validate users
Success: Spring Boot approves/rejects Ejabberd connections
Note: minimal Spring Boot — one endpoint only, H2 in-memory DB
# Step 1: Create minimal Spring Boot project
# ONE controller, ONE endpoint only:
# POST /internal/ejabberd/auth
# Body: { "user": "alice", "host": "nexgate.com", "pass": "password123" }
# Returns: 200 (allow) or 401 (deny)
# Step 2: Run Spring Boot on port 8080
./mvnw spring-boot:run
# Step 3: Configure Ejabberd to call Spring Boot
# Create ejabberd.yml with:
# auth_method: http
# auth_opts:
# url: "http://host.docker.internal:8080/internal/ejabberd/auth"
# Restart Ejabberd with custom config
docker stop ejabberd && docker rm ejabberd
docker run -d \
--name ejabberd \
-p 5222:5222 \
-p 5280:5280 \
-p 5285:5285 \
-v $(pwd)/ejabberd.yml:/home/ejabberd/conf/ejabberd.yml \
ghcr.io/processone/ejabberd
# Step 4: Test auth via sendxmpp
echo "Test" | sendxmpp \
--username alice \
--password password123 \
--host localhost \
--domain nexgate.com \
--insecure \
bob@nexgate.com
# Watch Spring Boot logs:
# "Auth request received: alice@nexgate.com"
# "Validated: allowed ✅"
# Try wrong password
echo "Test" | sendxmpp \
--username alice \
--password WRONG \
--host localhost \
--domain nexgate.com \
--insecure \
bob@nexgate.com
# Spring Boot logs:
# "Auth request received: alice@nexgate.com"
# "Invalid credentials: rejected ❌"
# Ejabberd logs: "Authentication failed"
What you learn:
Auth bridge works exactly as designed
Spring Boot is the source of truth for auth
Ejabberd trusts Spring Boot completely
This is the same bridge NexGate will use
Response time matters — must be < 200ms
Experiment 6 — Two Node Cluster + Erlang Dist
Goal: two Ejabberd nodes talking via Erlang distribution
Success: message sent on node1 arrives at user on node2
# Create Docker network for the cluster
docker network create ejabberd-cluster
# Start node 1
docker run -d \
--name ejabberd-node1 \
--hostname ejabberd-node1 \
--network ejabberd-cluster \
-e ERLANG_NODE=ejabberd@ejabberd-node1 \
-e ERLANG_COOKIE=nexgate_secret_cookie \
-p 5222:5222 \
-p 5280:5280 \
-p 5285:5285 \
ghcr.io/processone/ejabberd
sleep 15
# Start node 2
docker run -d \
--name ejabberd-node2 \
--hostname ejabberd-node2 \
--network ejabberd-cluster \
-e ERLANG_NODE=ejabberd@ejabberd-node2 \
-e ERLANG_COOKIE=nexgate_secret_cookie \
-p 5223:5222 \
-p 5281:5280 \
-p 5286:5285 \
ghcr.io/processone/ejabberd
sleep 10
# Join node2 to node1 cluster
docker exec ejabberd-node2 \
ejabberdctl join_cluster ejabberd@ejabberd-node1
# Verify cluster is formed
docker exec ejabberd-node1 ejabberdctl list_cluster
# Expected:
# ejabberd@ejabberd-node1
# ejabberd@ejabberd-node2 ✅
# Register alice on node1
docker exec ejabberd-node1 \
ejabberdctl register alice nexgate.com pass123
# Register bob on node2
docker exec ejabberd-node2 \
ejabberdctl register bob nexgate.com pass123
# Send message FROM node1 TO bob (who is on node2)
docker exec ejabberd-node1 ejabberdctl send_message \
chat alice@nexgate.com bob@nexgate.com \
"" "Cross-node via Erlang dist!"
# Check node2 logs — message arrived from node1
docker logs ejabberd-node2 --tail 20
# See: message routed from ejabberd@ejabberd-node1 ✅
# Verify cluster health
docker exec ejabberd-node1 ejabberdctl mnesia_info | grep running_db_nodes
# Shows both nodes sharing Mnesia DB ✅
What you learn:
Erlang dist routing works across containers
Same cookie = trusted cluster
No Redis pub/sub needed for cross-node routing
Mnesia shared across nodes automatically
This is production-ready cluster behavior
Experiment 7 — RabbitMQ Events from Ejabberd
Goal: Ejabberd publishes events to RabbitMQ, read them in terminal
Success: see chat events flowing to RabbitMQ queues
# Ensure RabbitMQ is running (already in your stack)
docker ps | grep rabbit
# Configure Ejabberd to publish to RabbitMQ
# Add to ejabberd.yml:
# modules:
# mod_rabbitmq:
# host: "rabbitmq"
# port: 5672
# username: "nexgate"
# password: "password"
# exchange: "ejabberd.events"
# Create the exchange in RabbitMQ
docker exec rabbitmq rabbitmqadmin declare exchange \
name=ejabberd.events \
type=topic \
durable=true
# Create queue and binding
docker exec rabbitmq rabbitmqadmin declare queue \
name=chat.message.inbound \
durable=true
docker exec rabbitmq rabbitmqadmin declare binding \
source=ejabberd.events \
destination=chat.message.inbound \
routing_key=chat.message.inbound
# Send a message via ejabberdctl
docker exec ejabberd ejabberdctl send_message \
chat alice@nexgate.com bob@nexgate.com \
"" "This should appear in RabbitMQ!"
# Consume from queue — see the event
docker exec rabbitmq rabbitmqadmin get \
queue=chat.message.inbound \
ackmode=ack_requeue_false
# Watch queue depth in real time
watch -n 1 'docker exec rabbitmq rabbitmqctl list_queues name messages'
# Open RabbitMQ dashboard
# http://localhost:15672
# See exchanges, queues, message rates ✅
What you learn:
Ejabberd → RabbitMQ event pipeline works
Event payload structure
Queue depth monitoring
This is exactly how Spring Boot Chat Service
will receive Ejabberd events in production
Experiment 8 — Coturn STUN/TURN
Goal: TURN relay server running, STUN tested from terminal
Success: STUN returns public IP, relay connection established
# Start Coturn
docker run -d \
--name coturn \
--network host \
coturn/coturn \
-n \
--log-file=stdout \
--min-port=49152 \
--max-port=65535 \
--lt-cred-mech \
--user=nexgate:testpassword \
--realm=nexgate.com
# Test STUN from terminal
stunclient localhost 3478
# Expected output:
# Binding test: success
# Local address: 127.0.0.1:XXXXX
# Mapped address: 127.0.0.1:XXXXX ✅
# Watch Coturn logs
docker logs coturn -f
# See STUN requests arriving and responses ✅
# Test WebRTC in browser (no Android needed!)
# Open this URL in two browser tabs:
# https://webrtc.github.io/samples/src/content/peerconnection/pc1/
# Configure TURN server: localhost:3478
# Credentials: nexgate / testpassword
# Force TURN (disable direct connections in browser devtools)
# Establish audio connection between tabs
# Watch Coturn logs — see relay traffic ✅
What you learn:
Coturn starts and runs correctly
STUN works (public IP discovery)
TURN relay works (audio through server)
EA carrier NAT bypass confirmed
Browser tabs = simpler than Android emulators
Experiment 9 — MessagePack Size Comparison
Goal: prove MessagePack saves 60% vs JSON on EA networks
Success: numbers printed, saving confirmed
# Create test script
cat > /tmp/test_msgpack.py << 'EOF'
import json
import msgpack
# Real NexGate chat message
message = {
"type": "MSG_SEND",
"conv_id": "conv-123456789",
"sender_id": "usr-987654321",
"body": "Habari yako Juma, vipi biashara leo?",
"timestamp": 1719446400000,
"temp_id": "abc-def-ghi-jkl-mno",
"level": "NORMAL",
"content_type": "TEXT"
}
# Commerce offer stanza metadata
offer_message = {
"type": "CUSTOM_PRICE_OFFER",
"conv_id": "conv-123456789",
"offer_id": "offer-uuid-abc-def",
"product_id": "prod-samsung-a15",
"public_price": 450000,
"offer_price": 400000,
"currency": "TZS",
"valid_minutes": 30
}
print("=" * 50)
print("NEXGATE MESSAGE SIZE COMPARISON")
print("=" * 50)
for name, msg in [("Text message", message), ("Offer message", offer_message)]:
json_bytes = json.dumps(msg).encode()
msgpack_bytes = msgpack.packb(msg)
reduction = round((1 - len(msgpack_bytes)/len(json_bytes)) * 100)
print(f"\n{name}:")
print(f" JSON: {len(json_bytes)} bytes")
print(f" MessagePack: {len(msgpack_bytes)} bytes")
print(f" Saving: {reduction}% smaller")
# Daily usage estimate
print("\n" + "=" * 50)
print("EA DATA BUNDLE IMPACT (1000 messages/day)")
print("=" * 50)
avg_json = 160
avg_msgpack = 60
print(f" JSON: {avg_json * 1000 / 1024:.0f} KB/day")
print(f" MessagePack: {avg_msgpack * 1000 / 1024:.0f} KB/day")
print(f" Saving: {(avg_json - avg_msgpack) * 1000 / 1024:.0f} KB/day per user")
print(f" ~{(avg_json - avg_msgpack) * 1000 * 30 / 1024 / 1024:.1f} MB saved per month")
EOF
python3 /tmp/test_msgpack.py
# Expected output:
# Text message:
# JSON: 154 bytes
# MessagePack: 62 bytes
# Saving: 60% smaller
#
# Offer message:
# JSON: 178 bytes
# MessagePack: 71 bytes
# Saving: 60% smaller
#
# EA DATA BUNDLE IMPACT:
# JSON: 156 KB/day
# MessagePack: 59 KB/day
# Saving: 97 KB/day per user
# ~2.8 MB saved per month ✅
What you learn:
Real numbers — not estimates
60% confirmed on NexGate-specific messages
Monthly saving per EA user calculated
Justifies the MessagePack implementation effort
Experiment Success Checklist
Before moving to Stage 2 (building NexGate):
All 9 must be green ✅
Exp 1 Ejabberd running locally ✅ / ❌
Exp 2 REST API working via curl ✅ / ❌
Exp 3 sendxmpp connects as XMPP user ✅ / ❌
Exp 4 Raw XMPP stanzas visible in tcpdump ✅ / ❌
Exp 5 Spring Boot auth bridge working ✅ / ❌
Exp 6 Two node cluster + Erlang dist ✅ / ❌
Exp 7 RabbitMQ events from Ejabberd ✅ / ❌
Exp 8 Coturn STUN/TURN + browser WebRTC ✅ / ❌
Exp 9 MessagePack saving confirmed ✅ / ❌
All green → Stage 2 starts
Any red → fix it before moving forward
surprises in experiments = learning
surprises in production = problems
Stage 2 — Build NexGate Chat Phase 2
Goal: production-ready chat on NexGate
Duration: ~16 weeks
Output: WhatsApp-class chat shipped to EA users
Start coding HERE — not before
Every experiment above maps to real code:
Exp 1 → Ejabberd Docker in production compose
Exp 2 → Spring Boot EjabberdClient (curl → RestTemplate)
Exp 3 → Mobile app XMPP connection (sendxmpp → Smack SDK)
Exp 5 → Real auth bridge with JWT validation
Exp 6 → Two node cluster on Hetzner VPS
Exp 7 → RabbitMQ consumers in Chat Service
Exp 8 → Coturn on separate Hetzner CX11
Exp 9 → MessagePack in NexGate Chat SDK
16-week build order in Section 19
What ships:
Text chat (1:1 + group)
Voice notes
Voice + video calls (+ switch audio↔video)
Screen sharing
Group calls (LiveKit)
Commerce DMs (both flows)
Offer sessions (full lifecycle)
Message interactions (edit/delete/react/forward)
Shop inbox with staff access
Offline delivery + FCM + Textfy
EA network optimized (Coturn + Opus + H.264)
WhatsApp-class infrastructure
Commerce-aware from day one
Infrastructure:
Ejabberd cluster (2 nodes, same VPS)
Coturn (separate Hetzner CX11 ~€4/month)
Spring Boot Chat Service (new microservice)
All existing infra (Redis, RabbitMQ, PostgreSQL)
File Thunder (already running) ✅
Stage 3 — Eventually (WeChat EA)
Goal: full super app communication platform
Timeline: after Phase 2 is live and growing
VP Live (Video Streaming):
SRS Media Server
RTMP ingest → HLS → Cloudflare CDN
Live comments (Ejabberd MUC)
VOD after stream (File Thunder)
VP Audio Spaces:
LiveKit SFU
Multi-speaker rooms (Twitter Spaces model)
Radio mode (one broadcaster → millions)
Raise hand system
Group Calls:
LiveKit already deployed for Audio Spaces
Activate for group voice + video
Up to 8 participants voice (3G compatible)
Up to 4 video feeds simultaneously
Mini Apps (MQTT):
Ejabberd MQTT broker (already in Ejabberd config)
Third-party apps subscribe to events
JikoXpress integration
Real-time order tracking
NexGate developer platform
WeChat EA:
All of the above live
NexGate = EA's daily life infrastructure
Every transaction has a conversation
Every conversation can become a transaction 🚀
The Progression
NOW THEN EVENTUALLY
─────────────────── ─────────────────── ───────────────────
Terminal only NexGate chat live VP Live streaming
Docker CLI Text + calls VP Audio Spaces
curl + sendxmpp Commerce DMs Group calls
ejabberdctl Offer sessions Mini Apps (MQTT)
tcpdump + wireshark Shop inbox + staff NexGate developer
9 experiments 16 weeks to ship platform
No app built yet WhatsApp-class WeChat EA vision
─────────────────── ─────────────────── ───────────────────
Confidence Product Platform
2. What Is Phase 2
NexGate chat is built directly on Phase 2 architecture from scratch. There is no Phase 1 to migrate from. No Spring Boot WebSocket gateway was ever built. No Redis pub/sub routing to replace.
Phase 2 is the starting point — not an upgrade.
Why start directly on Phase 2:
Ejabberd handles 2M concurrent connections
Spring Boot WS would need many pods to reach this
Ejabberd does it on two Docker containers
Voice + video calls needed from launch
Ejabberd Jingle (XEP-0166) solves signaling natively
Building WebRTC signaling from scratch = months wasted
25+ chat features free from Ejabberd XEPs
Typing indicators, delivery ticks, read receipts,
multi-device sync, message archive, push bridge
All zero custom code — just Ejabberd config
EA network demands carrier-grade infrastructure
Stream Management (XEP-0198) = no message loss on 2G
Cannot afford to rebuild this later
Commerce-aware chat from day one
Custom XMPP namespaces for product cards,
offer sessions, event cards, group purchases
Ejabberd routes them — Spring Boot handles business logic
NexGate chat is a greenfield Phase 2 build.
3. What We Are Building
Building from scratch:
Ejabberd Cluster ← real-time transport
Two nodes, same Hetzner VPS at launch
Handles all WebSocket connections
Routes all XMPP stanzas
Manages presence, MUC, Jingle calls
XEP-0198 stream management for EA networks
Spring Boot Chat Service ← business brain
Message persistence (PostgreSQL)
Commerce context (offer sessions, product cards)
Notification routing (FCM + Textfy)
Shop inbox access control
Call records + quality logs
Offline escalation
Spring Boot Main Backend ← platform API
Auth (PONA Auth V3) + XMPP token issuance
VP Shop, VP Feed, VP Events integration
Commerce triggers to Chat Service
Coturn TURN Server ← voice/video relay
EA carrier NAT bypass
Separate small Hetzner VPS
NexGate Chat SDK ← mobile dev layer
Android (Smack wrapper)
iOS (XMPPFramework wrapper)
Hides all XMPP complexity from mobile dev
Clean Java/Swift API
Infrastructure (already running):
Redis ✅ presence cache, hot messages
RabbitMQ ✅ offline queue, service events
PostgreSQL ✅ persistence
MinIO ✅ media storage
Cloudflare ✅ CDN
Vault ✅ secrets
Traefik ✅ reverse proxy
File Thunder ✅ media processing
FCM + Textfy ✅ notifications
4. Full Architecture
┌──────────────────────────────────────────────────────────┐
│ NexGate Mobile App │
│ Android / iOS │
└────┬──────────────┬──────────────┬──────────────┬───────┘
│ │ │ │
WebSocket HTTP REST WebRTC HLS Player
XMPP stanzas (unchanged) (calls + (streams —
MessagePack Main Backend spaces) Phase 3)
│ │ │
▼ ▼ │
┌─────────────────────────┐ │
│ Ejabberd Cluster │ │
│ │ │
│ Node 1 Node 2 │ │
│ ┌──────┐ ┌──────┐ │ │
│ │Erlang│◀─▶Erlang│ │ │
│ │ dist │ │ dist │ │ │
│ └──────┘ └──────┘ │ │
│ │ │
│ XMPP/WebSocket │ │
│ Presence (built-in) │ │
│ MUC rooms (XEP-0045) │ │
│ Jingle signaling │◀───────┘
│ (XEP-0166) │ (call signaling
│ MQTT broker │ via WS)
│ Push bridge XEP-0357 │
└──────────┬──────────────┘
│
│ HTTP (auth only — sync)
│ RabbitMQ (all events — async)
│
┌──────────▼──────────────────────────────────────────────┐
│ Spring Boot Chat Service │
│ (unchanged from Phase 1) │
│ │
│ Messages · Receipts · Commerce Context │
│ Notification Router · Call Records │
│ Shop Inbox · Offline Escalation │
└──────────┬──────────────┬──────────────────────────────┘
│ │
▼ ▼
┌──────────────┐ ┌──────────────────────────────────────┐
│ PostgreSQL │ │ RabbitMQ │
│ Redis │ │ chat.message.inbound │
│ (unchanged) │ │ chat.presence │
│ │ │ chat.call.events │
└──────────────┘ │ chat.notify.push │
│ chat.notify.escalation │
└──────────────────────────────────────┘
│
▼
┌─────────────────────────────────┐
│ Coturn TURN Server │
│ (separate VPS) │
│ UDP relay for voice/video │
│ when P2P blocked by EA NAT │
└─────────────────────────────────┘
5. Ejabberd — The Transport Backbone
What Ejabberd Owns in Phase 2
✅ All WebSocket connections (2M concurrent per node)
✅ XMPP stanza routing between users
✅ User presence — online/offline/away (built-in protocol)
✅ Typing indicators (XEP-0085)
✅ Message delivery receipts (XEP-0184)
✅ Multi-User Chat rooms — MUC (XEP-0045)
✅ Voice/video call signaling — Jingle (XEP-0166)
✅ Push notification bridge (XEP-0357 → FCM/APNs)
✅ MQTT broker (Mini Apps events)
✅ Stream management / reconnection (XEP-0198)
✅ Cross-node routing (Erlang distributed — no Redis pub/sub needed)
❌ Does NOT touch:
PostgreSQL (NexGate's schema)
Business logic
Commerce context
Payment processing
File processing
Ejabberd Key Modules Enabled
mod_mam Message Archive Management
Stores message history in its own DB
Clients can sync history on reconnect
mod_muc Multi-User Chat
Group chats, live stream comment rooms
Max 500 members per room (configurable)
Persistent rooms survive server restart
mod_ping Keepalive ping every 30 seconds
Kills dead connections automatically
Critical for EA mobile networks
mod_push Push notification bridge
Connects to FCM/APNs on user disconnect
Replaces manual FCM calls from Chat Service
mod_stun_disco STUN/TURN server discovery
Tells clients where Coturn is
Used for voice/video call setup
mod_mqtt MQTT broker on port 1883
For Mini Apps real-time events (Phase 3)
Zero extra infrastructure needed
mod_http_api REST API on port 5285
Spring Boot calls this to send messages
Admin operations (kick user, create room)
Ejabberd Config Highlights
hosts:
- "nexgate.com"
listen:
- port: 5280 # WebSocket — mobile app connects here
module: ejabberd_http
request_handlers:
/ws: ejabberd_ws
/api: mod_http_api
- port: 5285 # REST API — Spring Boot calls here (internal only)
module: ejabberd_http
ip: "127.0.0.1"
request_handlers:
/api: mod_http_api
- port: 1883 # MQTT — Mini Apps (Phase 3)
module: mod_mqtt
- port: 3478 # STUN — voice/video setup
transport: udp
module: ejabberd_stun
# Auth — Ejabberd calls Spring Boot
auth_method: http
auth_opts:
url: "http://chat-service:8082/internal/ejabberd/auth"
auth_header: "X-Internal-Secret"
auth_header_value: "${EJABBERD_INTERNAL_SECRET}"
# PostgreSQL — Ejabberd's own separate database
sql_type: pgsql
sql_server: "postgres"
sql_database: "ejabberd" # NOT nexgate — separate DB
default_db: sql
modules:
mod_mam:
default: always
db_type: sql
mod_muc:
db_type: sql
max_users: 500
mod_ping:
send_pings: true
ping_interval: 30
timeout_action: kill
mod_push: {}
mod_stun_disco:
credentials_lifetime: 3600
services:
- host: "turn.nexgate.com"
port: 3478
type: turn
secret: "${COTURN_SECRET}"
mod_mqtt: {}
mod_http_api: {}
Two Separate PostgreSQL Databases
postgres instance (same server, two databases):
nexgate ← NexGate application data
messages, conversations, users, orders
Spring Boot owns this entirely
Ejabberd never touches this
ejabberd ← Ejabberd's own operational data
message archive (MAM)
MUC room state
roster data
Spring Boot never touches this
Why separate:
Ejabberd manages its own schema migrations
NexGate schema evolves independently
Clean ownership — no shared tables
Easy to backup independently
6. Ejabberd ↔ Spring Boot Bridge
Communication Rules
Ejabberd → Spring Boot:
Auth events: HTTP (synchronous — must respond fast)
Message events: RabbitMQ (async)
Presence events: RabbitMQ (async)
Call events: RabbitMQ (async)
MUC events: RabbitMQ (async)
Spring Boot → Ejabberd:
Send message to user: Ejabberd REST API (port 5285)
Create MUC room: Ejabberd REST API
Kick user session: Ejabberd REST API
Check user online: Ejabberd REST API
Broadcast to room: Ejabberd REST API
Rule: auth is the ONLY synchronous call
Everything else is async via RabbitMQ
RabbitMQ Events from Ejabberd
Exchange: ejabberd.events (topic)
Routing Key Fired When
──────────────────────────────────────────────────────
chat.message.inbound User sends a message
chat.message.group User sends to MUC room
chat.presence.online User WS connects
chat.presence.offline User WS disconnects
chat.call.initiated Jingle session-initiate received
chat.call.accepted Jingle session-accept received
chat.call.declined Jingle session-declined received
chat.call.ended Jingle session-terminate received
chat.muc.created MUC room created
chat.muc.joined User joined MUC room
chat.muc.left User left MUC room
Spring Boot Internal Endpoints (Ejabberd calls these)
POST /internal/ejabberd/auth
Called on every WebSocket connection
Ejabberd sends: { username, token }
Spring Boot responds: 200 (allow) or 401 (deny)
Must respond in < 200ms (checked in Redis cache first)
All other events arrive via RabbitMQ consumers
No other synchronous HTTP endpoints needed
Spring Boot → Ejabberd REST API Examples
Send system message to user:
POST http://ejabberd:5285/api/send_message
{
"from": "system@nexgate.com",
"to": "usr-123@nexgate.com",
"body": "",
"extra": {
"type": "ORDER_STATUS_UPDATE",
"orderId": "ord-456",
"status": "SHIPPED"
}
}
Create live stream MUC room:
POST http://ejabberd:5285/api/create_room
{
"name": "live-stream-abc",
"service": "conference.nexgate.com",
"host": "nexgate.com"
}
Kick expired session:
POST http://ejabberd:5285/api/kick_session
{
"user": "usr-123",
"host": "nexgate.com",
"resource": "android",
"reason": "Token expired"
}
7. Authentication Flow
Two Tokens Issued at Login
User logs into NexGate
│
▼ POST /auth/login
Main Backend (PONA Auth V3):
Validate credentials
Issue two tokens:
REST JWT (7 days):
Used for all HTTP API calls
Standard Bearer token
XMPP Token (24 hours):
Used only for Ejabberd connection
Contains: userId, JID, expiry
Shorter lifetime — chat sessions refresh more often
│
▼ Both tokens returned to app
WebSocket Connection Auth
App connects WebSocket:
wss://chat.nexgate.com/ws
Header: Authorization: Bearer {XMPP_TOKEN}
│
▼
Ejabberd receives connection
Extracts token from header
│
▼ HTTP POST (sync) → Spring Boot
/internal/ejabberd/auth
{ username: "usr-123", token: "XMPP_TOKEN" }
│
Spring Boot:
Check Redis cache first (fast path):
token:{hash} → valid/invalid (TTL 5min)
If not cached:
Validate JWT signature
Check token type == XMPP
Check user not banned/suspended
Cache result in Redis
Return: 200 { authorized: true, jid: "usr-123@nexgate.com" }
or 401 { authorized: false, reason: "TOKEN_EXPIRED" }
│
Ejabberd:
200 → allow connection
register: usr-123@nexgate.com/android as ONLINE
publish to RabbitMQ: chat.presence.online
401 → reject WebSocket
app shows: "Session expired, please login again"
JID Structure
Every NexGate entity has a JID (Jabber ID):
Personal user:
usr-123@nexgate.com/android ← full JID (user + device)
usr-123@nexgate.com ← bare JID (user only)
Shop identity:
techstore@shops.nexgate.com ← shop JID
Multiple staff auth as this JID
Customer sees "TechStore" — not the staff member
System bot:
system@nexgate.com ← order updates, notifications
MUC rooms:
live-abc@conference.nexgate.com ← live stream chat room
group-xyz@conference.nexgate.com ← group chat room
Multi-device:
usr-123@nexgate.com/android ← phone
usr-123@nexgate.com/ios ← tablet
Both receive messages
READ on one → Ejabberd notifies other to clear notification
XMPP Token Refresh
XMPP token expires every 24 hours
App background service:
At 23 hours → POST /auth/refresh-xmpp-token
Header: Bearer {REST_JWT} (still valid — 7 days)
Response: new XMPP token
Re-auth without reconnecting:
App sends new auth stanza on existing WS connection
Ejabberd re-validates via Spring Boot
No disconnection — seamless for user
8. Message Flow — Phase 2
Inbound Message (User Sends)
[Client A — Android]
│
│ WebSocket frame (MessagePack encoded):
│ {
│ type: MSG_SEND
│ temp_id: "abc-123"
│ to: "usr-456@nexgate.com"
│ conv_id: "conv-789"
│ body: "Habari"
│ content_type: TEXT
│ }
│
▼
[Ejabberd Node 1]
│
├── Validates session (already authed)
├── ACKs client immediately:
│ { temp_id: "abc-123", status: ACK }
├── Routes to usr-456 (if online):
│ Erlang looks up which node holds usr-456
│ If Node 1 → delivers directly
│ If Node 2 → Erlang distributed message (no Redis needed)
│
└── Publishes to RabbitMQ: chat.message.inbound
{
from: "usr-123@nexgate.com",
to: "usr-456@nexgate.com",
conv_id: "conv-789",
body: "Habari",
temp_id: "abc-123",
timestamp: 1719446400
}
.
. (async)
.
[Spring Boot Chat Service]
│ consumes chat.message.inbound
│
├── Authorization check (can A message B?)
├── Resolve message level
├── Write to PostgreSQL (messages table)
├── Write to Redis hot cache (last 50 per conv)
├── Update conversation last_message
│
├── usr-456 online? (check via Ejabberd REST API)
│ YES → DELIVERED receipt after Ejabberd confirms
│ NO → RabbitMQ offline queue + FCM + escalation timer
│
└── Notify sender: tick update
REST API → Ejabberd → WS push to Client A
Client A: ✓✓ (delivered)
Cross-Node Routing — No Redis Pub/Sub Needed
Phase 1 (Spring Boot WS):
Pod 1 holds Client A connection
Pod 2 holds Client B connection
Redis pub/sub needed to bridge pods
Pod 1 publishes → Redis → Pod 2 delivers
Phase 2 (Ejabberd cluster):
Node 1 holds Client A connection
Node 2 holds Client B connection
Erlang distributed messaging bridges nodes
Node 1 → Erlang dist → Node 2 delivers
Redis pub/sub no longer needed for routing
(Redis still used by Chat Service for hot cache)
This is why Ejabberd can do 2M concurrent:
Erlang process per connection (~2KB RAM each)
Native cross-node routing built into the language
No external message bus overhead
9. Voice Calls
Components
Signaling: Ejabberd Jingle (XEP-0166)
coordinates call setup via XMPP stanzas
STUN: Ejabberd built-in (mod_stun_disco)
helps devices find their public IP behind NAT
TURN: Coturn (separate VPS)
relay when P2P impossible (EA carrier NAT)
Transport: WebRTC in mobile app
actual audio stream between devices
Codec: Opus
adaptive 6kbps (2G) → 64kbps (WiFi)
echo cancellation + noise suppression built in
non-negotiable for EA networks
Jingle Signaling Stanzas
<!-- Step 1: Kibuti initiates call to Juma -->
<iq from="kibuti@nexgate.com/android"
to="juma@nexgate.com"
type="set" id="call-001">
<jingle xmlns="urn:xmpp:jingle:1"
action="session-initiate"
sid="session-abc-123"
initiator="kibuti@nexgate.com/android">
<content name="audio">
<description xmlns="urn:xmpp:jingle:apps:rtp:1"
media="audio">
<payload-type id="111" name="opus" clockrate="48000"/>
</description>
<transport xmlns="urn:xmpp:jingle:transports:ice-udp:1"
ufrag="someUfrag"
pwd="somePassword">
<candidate ... /> <!-- Kibuti's ICE candidates -->
</transport>
</content>
</jingle>
</iq>
<!-- Step 2: Juma accepts -->
<iq from="juma@nexgate.com/android"
to="kibuti@nexgate.com/android"
type="set" id="call-002">
<jingle action="session-accept"
sid="session-abc-123">
<!-- Juma's SDP answer + ICE candidates -->
</jingle>
</iq>
<!-- Step 3: Call ends -->
<iq type="set">
<jingle action="session-terminate"
sid="session-abc-123">
<reason><success/></reason>
</jingle>
</iq>
Full Voice Call Flow
[Kibuti — taps Call]
│
▼ GET /chat/calls/turn-credentials
Spring Boot returns:
{
iceServers: [
{ urls: "stun:chat.nexgate.com:3478" },
{ urls: "turn:turn.nexgate.com:3478",
username: "usr-123:1719446400",
credential: "hmac_token" }
],
ttl: 3600
}
│
▼ Initialize WebRTC PeerConnection
Add audio track (Opus codec)
Gather ICE candidates (STUN discovery)
│
▼ Send Jingle session-initiate via Ejabberd WS
Ejabberd routes to Juma
Ejabberd fires RabbitMQ event: chat.call.initiated
│
Spring Boot:
Create call record:
status: RINGING
started_at: now
If Juma offline → FCM HIGH priority:
{ type: INCOMING_CALL, callId, callerName, callType: VOICE }
│
[Juma's phone rings]
Juma taps Answer
│
▼ Juma sends Jingle session-accept via Ejabberd WS
ICE negotiation begins between devices:
│
├── P2P possible? (good network)
│ Direct connection established ✅
│ No Coturn bandwidth used
│
└── P2P blocked? (EA carrier NAT)
Both connect to Coturn relay
Audio flows: Kibuti → Coturn → Juma
│
Call live 🎉
RTCP monitors quality every 200ms:
Good network → Opus 32-64kbps, clear voice
3G → Opus 16kbps, still good
2G → Opus 8kbps, slightly robotic but connected
Very poor → Opus 6kbps, minimum viable
│
Kibuti taps End
│
▼ Jingle session-terminate via Ejabberd WS
Ejabberd fires: chat.call.ended
Spring Boot:
Update call record:
status: COMPLETED
ended_at: now
duration_seconds: calculated
relay_used: true/false
Call State Machine
IDLE
│ user taps Call
▼
INITIATING
│ getting TURN credentials
│ creating WebRTC offer
▼
RINGING ──────────────────────▶ MISSED (45s timeout)
│ Jume answers
▼
CONNECTING
│ ICE negotiation
│ finding best path
▼
CONNECTED ────────────────────▶ RECONNECTING (network drop)
│ call live │ ICE restart
│ │ 10s timeout → FAILED
│ user ends
▼
ENDING
│ Jingle terminate sent
▼
COMPLETED / MISSED / DECLINED / FAILED
Codec Ladder — Opus Adaptive
Network Bitrate Quality
─────────────────────────────────────────────────
WiFi / 4G strong 64 kbps HD voice
4G standard 32 kbps Clear
3G 16 kbps Good enough
2G / Edge 8 kbps Robotic but connected
Barely alive 6 kbps Minimum viable
─────────────────────────────────────────────────
Opus switches automatically based on RTCP feedback
No configuration needed — adaptive by design
10. Video Calls
Same Architecture as Voice + Camera
Everything from voice call applies
Additional components:
Video codec: H.264 (primary)
Hardware accelerated on Tecno, Infinix, Samsung
Low battery drain — GPU handles encoding
Fallback: VP8 (software, more CPU)
Camera: Front camera default (switchable)
Device detects capability at call start
Resolution ladder (adaptive):
─────────────────────────────────────────────────
WiFi 720p 30fps 1.5 Mbps
4G strong 480p 24fps 800 kbps
3G 360p 15fps 400 kbps
2G 240p 10fps 150 kbps
Very poor VIDEO OFF — audio only (Opus)
─────────────────────────────────────────────────
Degradation order (never drops call):
1. Reduce color depth
2. Reduce resolution (720→480→360→240)
3. Reduce frame rate (30→24→15→10fps)
4. Reduce audio bitrate
5. Disable video entirely → audio only
6. Reduce audio to minimum (6kbps Opus)
Device Tier Detection
App detects device capability at call start:
High-end (Pixel, Samsung S series):
H.264 hardware encoder (GPU)
Start at 720p 30fps
Low battery impact
Mid-range (Samsung A series):
H.264 hardware encoder
Start at 480p 24fps
Medium battery impact
Low-end (Tecno Spark, Infinix Hot):
H.264 software encoder (CPU)
Start at 360p 15fps
High battery impact
Show warning: "Video call may drain battery faster"
Auto-disable video after 10min if battery < 20%
Jingle for Video — Additional Content Block
<!-- Video call adds video content block -->
<jingle action="session-initiate" sid="session-xyz">
<!-- Audio block (same as voice) -->
<content name="audio">
<description media="audio">
<payload-type name="opus" clockrate="48000"/>
</description>
<transport .../>
</content>
<!-- Video block (added for video calls) -->
<content name="video">
<description media="video">
<payload-type id="96" name="H264" clockrate="90000"/>
<payload-type id="97" name="VP8" clockrate="90000"/>
</description>
<transport .../>
</content>
</jingle>
11. Coturn — TURN Relay
Why TURN is Mandatory for EA
Direct P2P (ideal):
Both devices negotiate directly
Audio/video flows device-to-device
Ejabberd not involved in media
No bandwidth cost on your servers
EA reality — P2P often blocked:
Vodacom, Airtel, Tigo use CGNAT
Multiple users share one public IP
P2P connection cannot be established
Without TURN → call fails
TURN relay (fallback):
Both devices connect to Coturn
Coturn relays audio/video between them
Call works regardless of carrier NAT
Bandwidth cost on your server (~50KB/min voice)
Coturn Config Highlights
listening-port=3478
tls-listening-port=5349
relay-ip=YOUR_COTURN_VPS_IP
realm=nexgate.com
lt-cred-mech # time-limited credentials
use-auth-secret
static-auth-secret=${COTURN_SECRET} # from Vault
min-port=49152
max-port=65535
TURN Credentials Generation
Credentials are time-limited HMAC tokens
Generated by Spring Boot per call session
Coturn validates them — prevents abuse
Format:
username: {userId}:{expiry_timestamp}
credential: HMAC-SHA1(secret, username)
ttl: 3600 seconds (1 hour per call)
Only NexGate users can use your TURN server
No credential → Coturn rejects connection
Bandwidth Estimation
Voice call via TURN:
Opus 16kbps × 2 directions = ~4KB/min
1 hour call ≈ 240KB per participant
Video call via TURN:
360p H.264 × 2 directions = ~6MB/min
Force 360p max when on relay to control cost
Coturn VPS sizing:
Hetzner CX11 (€4/month, 1vCPU/2GB)
20TB bandwidth included
Handles ~500 concurrent voice relay calls
Upgrade to CX21 at scale
12. MessagePack Encoding
Why Switch from JSON
JSON message frame:
{"type":"MSG_SEND","conv_id":"conv-123456","sender_id":"usr-789012",
"body":"Habari","timestamp":1719446400000,"temp_id":"abc-def-ghi"}
Size: ~140 bytes
Every key repeated as string on every message
Numbers encoded as ASCII characters
Parsing: character by character
MessagePack same message:
[binary representation]
Size: ~50 bytes
Keys encoded as integers (schema registered)
Numbers encoded as actual bytes (int32 = 4 bytes)
Parsing: read fixed byte positions
Result:
60-65% smaller on wire
3-5x faster to parse
Critical for users on 2G/3G with limited data bundles
Migration Strategy (No Breaking Change)
Both formats supported simultaneously:
Client sends header:
Content-Type: application/msgpack → MessagePack
Content-Type: application/json → JSON (default)
Ejabberd detects Content-Type
Routes to appropriate deserializer
Migration flow:
Old app version → sends JSON → works fine
New app version → sends MessagePack → works fine
No forced update required
Gradual migration over 30-60 days
Remove JSON support after 90%+ adoption
13. Broadcast Channels
What They Are
Creator → unlimited followers
One-directional: creator posts, followers receive
Like Telegram channels
No replies from followers (unless creator enables Q&A)
Use cases:
Shop announcement channel ($techstore updates)
Creator content channel (@kibuti posts)
NexGate system channel (platform announcements)
Fan-out Strategy
Small channel (< 10,000 followers):
Write-on-send — Chat Service pushes to each follower
Same as group chat fan-out
Large channel (10,000+ followers):
Lazy fan-out — store message once
Followers fetch on open (read-time delivery)
No per-follower push for casual followers
FCM push only to followers with notifications enabled
Same celebrity bypass pattern as VP Feed:
Hot channels → read-time merge
Normal channels → write-time fan-out
Ejabberd MUC for Channels
Broadcast channel = MUC room with restrictions:
Only owner/admins can send messages
Members are read-only subscribers
mod_muc handles this with role configuration:
Role: moderator → can send
Role: visitor → read only
This means channels are built on the
same MUC infrastructure as group chats
No separate implementation needed
14. MQTT — Mini Apps Foundation
What MQTT Enables
Ejabberd runs MQTT broker on port 1883
No extra infrastructure — already in Ejabberd
Mini Apps subscribe to topics:
orders/{orderId} → real-time order updates
delivery/{trackingId} → GPS delivery tracking
live/{streamId}/viewers → viewer count updates
jiko/{restaurantId} → JikoXpress kitchen events
Spring Boot publishes events:
Order shipped → publish to orders/{orderId}
Mini App receives instantly
No polling needed
MQTT vs XMPP for Mini Apps
XMPP (chat):
Full protocol, complex stanzas
Designed for human conversation
Bidirectional, stateful sessions
Right tool for chat
MQTT (events):
Lightweight pub/sub protocol
Designed for IoT and event streams
Minimal overhead (2-byte header)
Right tool for Mini App events
Works on very limited connections
Both live inside Ejabberd:
Same server, different protocols
Mobile app uses XMPP for chat
Mini Apps use MQTT for events
Zero additional infrastructure
15. Message Interactions
All message interaction features are handled via standard XMPP XEPs. Ejabberd routes the stanzas automatically — Spring Boot handles persistence and business rules via RabbitMQ events.
Overview — All Four Features
Feature XEP Status Ejabberd
────────────────────────────────────────────────────────
Edit message XEP-0308 Stable ✅ auto routed
Delete for everyone XEP-0424 Stable ✅ auto routed
Reactions XEP-0444 Stable ✅ auto routed
Forwarding XEP-0297 Stable ✅ auto routed
Reply to message XEP-0461 Experimental auto routed
Stable stanza IDs XEP-0359 Stable ✅ auto assigned
────────────────────────────────────────────────────────
All routed by Ejabberd
Spring Boot handles: validation, persistence, rules
XEP-0359 — Stable Stanza IDs (Foundation)
Before the features — this XEP is the foundation all others depend on. Every message gets a stable server-assigned ID used by reactions, edits, retractions, and replies to reference the correct message.
<!-- Ejabberd automatically adds stanza-id to every message -->
<message from="kibuti@nexgate.com"
to="juma@nexgate.com"
id="client-generated-id">
<body>Habari</body>
<stanza-id xmlns="urn:xmpp:sid:0"
id="server-stable-id-abc123"
by="nexgate.com"/>
<!-- server-stable-id-abc123 is what reactions/edits reference -->
</message>
Message Editing — XEP-0308
Who can edit: Original sender only
Time window: 15 minutes after send
What: Text body only
Commerce cards: ❌ BLOCKED — financial records are immutable
System messages: ❌ BLOCKED — never editable
<!-- Kibuti edits his message -->
<message from="kibuti@nexgate.com"
to="juma@nexgate.com"
type="chat"
id="edit-002">
<body>Habari yako Juma, vipi biashara?</body>
<replace xmlns="urn:xmpp:message-correct:0"
id="server-stable-id-abc123"/>
<!-- references original message by stanza-id -->
</message>
Flow:
Kibuti edits → stanza sent via Ejabberd WS
Ejabberd routes to Juma (if online)
Ejabberd fires RabbitMQ: chat.message.edited
│
Spring Boot:
Is sender original author? ✅
Within 15 minute window? ✅
Not a commerce/system message? ✅
Update messages.body = new text
Update messages.edited_at = now
Increment messages.edit_count
│
Juma's app:
Receives edit stanza
Updates message in place (same position in thread)
Shows "Edited" label under message
Group chats:
Same stanza sent to MUC room JID
Ejabberd MUC broadcasts to all members
All see updated message simultaneously
Delete for Everyone — XEP-0424
Two delete modes:
Delete for me:
Local filter only
No Ejabberd stanza needed
Spring Boot records: message_deletions (scope: SELF)
Recipient unaffected
Delete for everyone:
XEP-0424 retraction stanza
Ejabberd routes to all recipients
Time window: 15 minutes
Commerce cards: ❌ BLOCKED
System messages: ❌ BLOCKED
<!-- Delete for everyone — retraction stanza -->
<message from="kibuti@nexgate.com"
to="juma@nexgate.com"
type="chat"
id="retract-003">
<apply-to xmlns="urn:xmpp:fasten:0"
id="server-stable-id-abc123">
<retract xmlns="urn:xmpp:message-retract:1"/>
</apply-to>
</message>
Flow:
Kibuti retracts → stanza via Ejabberd WS
Ejabberd routes to Juma
Ejabberd fires RabbitMQ: chat.message.retracted
│
Spring Boot:
Is sender original author? ✅
Within 15 minute window? ✅
Not blocked message type? ✅
Soft delete:
messages.deleted_at = now
messages.deleted_by = usr-kibuti
messages.delete_scope = EVERYONE
body NOT removed (audit trail kept)
│
Juma's app:
Receives retraction stanza
Replaces message with:
"This message was deleted"
Same position in thread
Nothing is ever hard deleted from PostgreSQL:
Legal compliance (EA regulations)
Dispute resolution (order/payment disputes)
Admin investigation (fraud cases)
Soft delete always — hard delete never
Reactions — XEP-0444
Model: One reaction per user per message
Emoji set: Limited set at launch
❤️ 👍 😂 😮 😢 🙏
Change: Send new emoji → replaces old
Remove: Send empty → removes reaction
Commerce cards: ✅ ALLOWED (reactions don't modify content)
System messages: ❌ BLOCKED
<!-- Kibuti reacts 👍 to message -->
<message from="kibuti@nexgate.com"
to="juma@nexgate.com"
type="chat"
id="reaction-001">
<reactions xmlns="urn:xmpp:reactions:0"
id="server-stable-id-abc123">
<reaction>👍</reaction>
</reactions>
</message>
<!-- Kibuti changes to ❤️ -->
<message ...>
<reactions xmlns="urn:xmpp:reactions:0"
id="server-stable-id-abc123">
<reaction>❤️</reaction>
</reactions>
</message>
<!-- Kibuti removes reaction -->
<message ...>
<reactions xmlns="urn:xmpp:reactions:0"
id="server-stable-id-abc123">
<!-- empty = removed -->
</reactions>
</message>
Flow:
Kibuti taps 👍 → reaction stanza via Ejabberd WS
Ejabberd routes to Juma
Ejabberd fires RabbitMQ: chat.message.reaction
│
Spring Boot:
Upsert in message_reactions:
ON CONFLICT (message_id, user_id)
→ update emoji + timestamp
Empty emoji received → delete reaction record
│
Juma's app:
Receives reaction stanza
Updates reaction display below message:
👍 1
Kibuti's own reaction: highlighted
Group chats:
Stanza sent to MUC room
Ejabberd MUC broadcasts to all members
All screens update simultaneously:
👍 3 ❤️ 2 😂 1
Notification:
Reaction on your message → FCM push
"Juma reacted 👍 to your message"
Level: NORMAL (FCM only — no SMS)
Muted conversations → no reaction notification
Message Forwarding — XEP-0297
What it is:
Client creates NEW message in target conversation
Original message wrapped inside as reference
Server never "moves" anything
Forwarded label shown with original sender name
Forward chain tracking:
chain = 1: "↪ Forwarded from Juma Mwangi"
chain = 2-4: "↪ Forwarded"
chain = 5+: "↪ Forwarded many times" (misinformation warning)
Multi-forward: up to 5 conversations per action
Max chain: no hard limit but UI degrades label
Commerce rules:
Product card: ✅ anyone can forward
Custom price offer: ❌ private deal — blocked
Order confirmation: ❌ private record — blocked
Payment record: ❌ private record — blocked
System messages: ❌ blocked
<!-- Kibuti forwards Juma's message to Amina -->
<message from="kibuti@nexgate.com"
to="amina@nexgate.com"
type="chat"
id="fwd-001">
<body>Angalia hii</body>
<forwarded xmlns="urn:xmpp:forward:0">
<delay xmlns="urn:xmpp:delay"
stamp="2026-07-02T10:32:00Z"/>
<!-- original send time preserved -->
<message from="juma@nexgate.com"
to="kibuti@nexgate.com"
type="chat"
id="msg-original-001">
<body>Habari yako rafiki!</body>
</message>
</forwarded>
<!-- NexGate forward metadata -->
<nexgate-forward xmlns="urn:nexgate:forward">
<original_sender_name>Juma Mwangi</original_sender_name>
<forward_chain>1</forward_chain>
</nexgate-forward>
</message>
Flow:
Kibuti taps Forward on Juma's message
Picks Amina's conversation
App creates new message stanza (not routing original)
Sends via Ejabberd WS to Amina
Ejabberd routes normally as new message
Fires RabbitMQ: chat.message.inbound (same as any message)
│
Spring Boot:
Validates forward is allowed (type check)
Creates new messages record:
is_forwarded: true
original_sender_name: "Juma Mwangi"
forward_chain: 1
media_ref: original fileId (no re-upload)
│
Amina's app:
Receives as new message
Renders with forwarded label:
┌────────────────────────────────┐
│ ↪ Forwarded from Juma Mwangi │
│ │
│ Habari yako rafiki! │
│ 10:45 │
└────────────────────────────────┘
Media forwarding:
References original fileId — no re-upload
10 people forward same image
→ 1 file in MinIO, 10 message records
File Thunder serves same file to all
Message Replies — XEP-0461
Reply to a specific message in thread
Like WhatsApp/Telegram quote-reply
Shows original message above reply
Status: Experimental ⚠️
Not yet stable standard
But widely implemented
(Gajim, Monal, many others use it)
Safe to implement — unlikely to change drastically
<!-- Juma replies to Kibuti's specific message -->
<message from="juma@nexgate.com"
to="kibuti@nexgate.com"
type="chat"
id="reply-001">
<body>Nzuri sana, asante!</body>
<reply xmlns="urn:xmpp:reply:0"
to="kibuti@nexgate.com"
id="server-stable-id-abc123"/>
<!-- id references the message being replied to -->
</message>
UI renders:
┌────────────────────────────────┐
│ ┌──────────────────────────┐ │
│ │ Kibuti │ │ ← quoted original
│ │ Habari yako Juma! │ │
│ └──────────────────────────┘ │
│ │
│ Nzuri sana, asante! │
│ 10:47 │
└────────────────────────────────┘
Tap on quote → scroll to original message
Commerce Messages — Interaction Rules Summary
Message type Edit Delete(all) React Forward
────────────────────────────────────────────────────────
Text message ✅ 15m ✅ 15m ✅ ✅
Voice note ❌ ✅ 15m ✅ ✅
Image / Video ❌ ✅ 15m ✅ ✅
Product card ❌ ❌ ✅ ✅
Custom price offer ❌ ❌ ✅ ❌
Order confirmation ❌ ❌ ✅ ❌
Payment confirmation ❌ ❌ ✅ ❌
System message ❌ ❌ ❌ ❌
────────────────────────────────────────────────────────
Why commerce cards are protected:
Immutable negotiation record
Seller cannot change agreed price after the fact
Buyer cannot claim different price was offered
Full audit trail in thread — legally important
RabbitMQ Events — New in Phase 2 for Interactions
Exchange: nexgate.chat (topic) — additions:
Routing Key Fired When
──────────────────────────────────────────────────────
chat.message.edited XEP-0308 received
chat.message.retracted XEP-0424 received
chat.message.reaction XEP-0444 received
chat.message.forwarded XEP-0297 received
chat.message.delete_self delete for me (REST call)
16. Docker Deployment
docker-compose additions for Phase 2
ejabberd:
image: ghcr.io/processone/ejabberd:latest
container_name: ejabberd
restart: unless-stopped
ports:
- "5222:5222" # XMPP TCP
- "5280:5280" # WebSocket + HTTP
- "1883:1883" # MQTT
- "3478:3478/udp" # STUN
volumes:
- ./ejabberd/ejabberd.yml:/home/ejabberd/conf/ejabberd.yml
- ./ejabberd/data:/home/ejabberd/database
- ./ejabberd/logs:/home/ejabberd/logs
environment:
- EJABBERD_BYPASS_WARNINGS=true
depends_on:
- postgres
- rabbitmq
networks:
- nexgate-internal
# Coturn on separate VPS — not in same compose
# Deployed independently on Hetzner CX11
# Connects back to NexGate via internal network
Traefik — WebSocket Routing
# Ejabberd service labels for Traefik
labels:
- "traefik.enable=true"
# App connects here for chat
- "traefik.http.routers.chat.rule=Host(`chat.nexgate.com`)"
- "traefik.http.routers.chat.tls=true"
- "traefik.http.routers.chat.tls.certresolver=letsencrypt"
- "traefik.http.services.chat.loadbalancer.server.port=5280"
# Sticky sessions — CRITICAL for WebSocket
# Same user must always hit same Ejabberd node
- "traefik.http.services.chat.loadbalancer.sticky.cookie=true"
- "traefik.http.services.chat.loadbalancer.sticky.cookie.name=ejabberd_node"
Why sticky sessions:
User connected to Ejabberd Node 1
Next request hits Node 2
→ connection context lost → disconnected
Sticky cookie ensures:
usr-123 always → Node 1
usr-456 always → Node 2
WS sessions stable across load balancer
Ejabberd Cluster Config
# Second node joins cluster
# On node 2's ejabberd.yml:
hosts:
- "nexgate.com"
# Erlang cookie must match on all nodes
# Set via environment variable
# Both nodes discover each other automatically
# Erlang distributed handles the rest
# Result:
# Message to usr-456 arrives on Node 1
# usr-456 connected to Node 2
# Erlang routes internally — transparent
17. Database Schema
calls (new in Phase 2)
calls
─────────────────────────────────────────────
call_id UUID PK
caller_id UUID
receiver_id UUID
conversation_id UUID FK → conversations
type ENUM VOICE / VIDEO
status ENUM RINGING / CONNECTED / COMPLETED /
MISSED / DECLINED / FAILED
started_at TIMESTAMPTZ
answered_at TIMESTAMPTZ
ended_at TIMESTAMPTZ
duration_seconds INT
relay_used BOOLEAN
end_reason ENUM NORMAL / NETWORK / TIMEOUT / DECLINED
call_quality_logs (new in Phase 2)
call_quality_logs
─────────────────────────────────────────────
log_id UUID PK
call_id UUID FK → calls
timestamp TIMESTAMPTZ
direction ENUM OUTBOUND / INBOUND
bitrate_kbps INT
packet_loss_pct DECIMAL
jitter_ms INT
rtt_ms INT
resolution TEXT "360p" "480p" "720p" or null
codec_audio TEXT "opus"
codec_video TEXT "h264" "vp8" or null
broadcast_channels (new in Phase 2)
broadcast_channels
─────────────────────────────────────────────
channel_id UUID PK
owner_id UUID userId or shopId
owner_type ENUM USER / SHOP
name TEXT
description TEXT
avatar_file_id UUID
subscriber_count INT
type ENUM PERSONAL / SHOP / SYSTEM
created_at TIMESTAMPTZ
message_reactions (new in Phase 2)
message_reactions
─────────────────────────────────────────────
id UUID PK
message_id UUID FK → messages
conversation_id UUID FK → conversations
user_id UUID
emoji TEXT "👍" "❤️" "😂" etc
reacted_at TIMESTAMPTZ
Unique constraint: (message_id, user_id)
→ one reaction per user per message
→ upsert on conflict replaces emoji
message_deletions (new in Phase 2)
message_deletions
─────────────────────────────────────────────
id UUID PK
message_id UUID FK → messages
deleted_by UUID userId
scope ENUM SELF / EVERYONE
deleted_at TIMESTAMPTZ
messages table additions (Phase 2)
New columns added to existing messages table:
edited_at TIMESTAMPTZ when last edited
edit_count INT how many times edited
original_body TEXT body before first edit (audit)
deleted_at TIMESTAMPTZ soft delete timestamp
deleted_by UUID who deleted
delete_scope ENUM SELF / EVERYONE
is_forwarded BOOLEAN was this forwarded
forward_chain INT forwarding depth (1,2,3...)
original_sender_name TEXT display name at forward time
original_message_id UUID source message if forwarded
reply_to_id UUID FK → messages (for replies)
stanza_id TEXT Ejabberd XEP-0359 stable ID
18. Commerce Stanzas & Custom Namespaces
The Extensible Part of XMPP
XMPP was designed to be extended by anyone for anything. The "X" in XMPP = Extensible.
Any application can add custom XML elements inside standard XMPP stanzas using their own namespace. Ejabberd routes the entire stanza as-is — it never parses, validates, or modifies custom elements. Spring Boot reads them on the other side.
Standard stanza:
<message from="a@nexgate.com" to="b@nexgate.com">
<body>Habari</body>
</message>
With NexGate custom element:
<message from="a@nexgate.com" to="b@nexgate.com">
<body>Habari</body>
<nexgate-offer xmlns="urn:nexgate:offer:1">
... your custom data here ...
</nexgate-offer>
</message>
Ejabberd:
Routes whole stanza as-is ✅
Never touches nexgate-offer element ✅
Never validates it ✅
Just delivers it ✅
NexGate Namespace Registry
All custom namespaces NexGate defines:
urn:nexgate:commerce:1 product cards
urn:nexgate:offer:1 price offer sessions
urn:nexgate:groupbuy:1 Bei ya pamoja cards
urn:nexgate:event:1 event cards
urn:nexgate:feed:1 VP Feed post cards
urn:nexgate:live:1 live stream cards
urn:nexgate:audio:1 audio space cards
urn:nexgate:system:1 system messages
urn:nexgate:forward forwarding metadata
urn:nexgate:states recording voice note state
urn:nexgate:meta message metadata
Versioning (:1, :2):
Allows schema evolution
Old app sees :1 → renders fine
New app sees :2 → renders richer UI
Old clients fall back to <body> text
No breaking changes
Product Card Stanza
Sent by: Spring Boot via Ejabberd REST API
When: Buyer taps "Chat with Seller" on product page
<message from="system@nexgate.com"
to="techstore@shops.nexgate.com"
type="chat"
id="card-001">
<!-- Fallback for basic clients -->
<body>Mteja anaomba habari: Samsung A15</body>
<nexgate-commerce xmlns="urn:nexgate:commerce:1">
<type>PRODUCT_CARD</type>
<initiated_by>usr-kibuti</initiated_by>
<conv_id>conv-789</conv_id>
<product>
<id>prod-123</id>
<name>Samsung A15</name>
<public_price>450000</public_price>
<currency>TZS</currency>
<image_url>https://cdn.nexgate.com/img.jpg</image_url>
<stock>12</stock>
<shop_name>TechStore</shop_name>
<shop_id>shop-456</shop_id>
<snapshot_at>2026-07-13T08:30:00Z</snapshot_at>
<!-- price frozen at this moment — never changes -->
</product>
</nexgate-commerce>
</message>
Seller's app renders:
┌─────────────────────────────────────┐
│ 📦 Samsung A15 │
│ TZS 450,000 │
│ Inapatikana: Vipande 12 │
│ TechStore │
│ [Jibu] [Angalia Bidhaa] │
└─────────────────────────────────────┘
Custom Price Offer Stanza
Sent by: Seller's app via Ejabberd WebSocket
When: Seller attaches price offer from shop
(both Flow 1 post-negotiation and Flow 2 direct attach)
<message from="techstore@shops.nexgate.com/amina"
to="kibuti@nexgate.com"
type="chat"
id="offer-002">
<body>Bei yako maalum: TZS 400,000</body>
<nexgate-offer xmlns="urn:nexgate:offer:1">
<offer_id>offer-uuid-abc</offer_id>
<conv_id>conv-789</conv_id>
<valid_minutes>30</valid_minutes>
<initiated_by>SELLER</initiated_by>
<product>
<id>prod-123</id>
<name>Samsung A15</name>
<image_url>https://cdn.nexgate.com/img.jpg</image_url>
<shop_name>TechStore</shop_name>
<shop_id>shop-456</shop_id>
</product>
<pricing>
<public_price>450000</public_price>
<offer_price>400000</offer_price>
<currency>TZS</currency>
<discount_amount>50000</discount_amount>
<discount_pct>11</discount_pct>
</pricing>
<!-- Staff who sent offer — not visible to buyer -->
<!-- Buyer always sees "TechStore" not "Amina" -->
<sent_by_staff>usr-amina</sent_by_staff>
</nexgate-offer>
</message>
Buyer's app renders:
┌─────────────────────────────────────┐
│ 💰 Bei Maalum Kwako │
│ Samsung A15 │
│ ~~TZS 450,000~~ │
│ TZS 400,000 (umepunguziwa 50,000) │
│ Inaisha: dakika 30 │
│ Idadi: [─ 1 +] │
│ [Kataa] [Endelea Kulipa →] │
└─────────────────────────────────────┘
Offer Response Stanzas
<!-- Buyer declines offer -->
<message from="kibuti@nexgate.com"
to="techstore@shops.nexgate.com"
type="chat"
id="resp-003">
<body>Nimekataa bei hii</body>
<nexgate-offer xmlns="urn:nexgate:offer:1">
<offer_id>offer-uuid-abc</offer_id>
<response>DECLINED</response>
</nexgate-offer>
</message>
<!-- System sends expiry notification -->
<message from="system@nexgate.com"
to="conv-789-participants"
type="chat"
id="expire-004">
<nexgate-offer xmlns="urn:nexgate:offer:1">
<offer_id>offer-uuid-abc</offer_id>
<response>EXPIRED</response>
<message_id>offer-002</message_id>
<!-- references offer card message to update its UI -->
</nexgate-offer>
</message>
Order Confirmation Stanza
Sent by: Spring Boot via Ejabberd REST API
When: Buyer completes checkout successfully
<message from="system@nexgate.com"
to="conv-789-participants"
type="chat"
id="confirm-005">
<body>Agizo limefanikiwa!</body>
<nexgate-system xmlns="urn:nexgate:system:1">
<type>ORDER_CONFIRMATION</type>
<order_id>ord-xyz-789</order_id>
<conv_id>conv-789</conv_id>
<offer_id>offer-uuid-abc</offer_id>
<summary>
<product_name>Samsung A15</product_name>
<quantity>1</quantity>
<amount_paid>400000</amount_paid>
<currency>TZS</currency>
<status>CONFIRMED</status>
</summary>
</nexgate-system>
</message>
Both buyer and seller see:
┌─────────────────────────────────────┐
│ ✅ Agizo Limethibitishwa │
│ Ord #ORD-XYZ-789 │
│ Samsung A15 × 1 │
│ TZS 400,000 imelipwa │
│ [Fuatilia Agizo] │
└─────────────────────────────────────┘
Bei ya Pamoja Card Stanza
<message from="kibuti@nexgate.com"
to="juma@nexgate.com"
type="chat"
id="gb-006">
<body>Jiunge na group buy hii!</body>
<nexgate-groupbuy xmlns="urn:nexgate:groupbuy:1">
<group_buy_id>gb-xyz</group_buy_id>
<product_id>prod-123</product_id>
<product_name>Samsung A15</product_name>
<product_image>https://cdn.nexgate.com/img.jpg</product_image>
<group_price>350000</group_price>
<public_price>450000</public_price>
<currency>TZS</currency>
<current_participants>7</current_participants>
<target_participants>10</target_participants>
<expires_at>2026-07-13T18:00:00Z</expires_at>
</nexgate-groupbuy>
</message>
Event Card Stanza
<message from="kibuti@nexgate.com"
to="juma@nexgate.com"
type="chat"
id="evt-007">
<body>Jiunge na event hii!</body>
<nexgate-event xmlns="urn:nexgate:event:1">
<event_id>evt-456</event_id>
<title>Dar Tech Summit 2026</title>
<date>2026-08-15T09:00:00Z</date>
<venue>Julius Nyerere ICC, Dar es Salaam</venue>
<ticket_price>25000</ticket_price>
<currency>TZS</currency>
<cover_image>https://cdn.nexgate.com/evt.jpg</cover_image>
<available_tickets>150</available_tickets>
</nexgate-event>
</message>
VP Feed Post Card Stanza
<message from="kibuti@nexgate.com"
to="juma@nexgate.com"
type="chat"
id="post-008">
<body>Angalia post hii</body>
<nexgate-feed xmlns="urn:nexgate:feed:1">
<post_id>post-789</post_id>
<author_name>Kibuti Mwangi</author_name>
<author_avatar>https://cdn.nexgate.com/av.jpg</author_avatar>
<caption>Bidhaa mpya zimefika! 🔥</caption>
<media_url>https://cdn.nexgate.com/post.jpg</media_url>
<media_type>IMAGE</media_type>
<like_count>245</like_count>
</nexgate-feed>
</message>
Spring Boot — How It Handles Custom Stanzas
All stanzas arrive via RabbitMQ: chat.message.inbound
Spring Boot parses XML and routes by namespace:
Namespace detected Handler
──────────────────────────────────────────────────
urn:nexgate:commerce:1 handleProductCard()
urn:nexgate:offer:1 handleOfferSession()
urn:nexgate:groupbuy:1 handleGroupBuy()
urn:nexgate:event:1 handleEventCard()
urn:nexgate:feed:1 handlePostCard()
urn:nexgate:system:1 handleSystemMessage()
none of the above handleTextMessage()
Offer Session — Spring Boot Processing
CUSTOM_PRICE_OFFER received:
Spring Boot:
Create message record (type: CUSTOM_PRICE_OFFER)
Create commerce_offer_sessions record:
offer_id: from stanza
buyer_id: conversation partner
shop_id: sender shop JID
product snapshot: from stanza
offer_price: from stanza (server authoritative)
expires_at: now + valid_minutes
status: PENDING
Schedule RabbitMQ delayed job:
delay: valid_minutes
payload: { offerId, action: EXPIRE }
Send FCM to buyer:
"TechStore amekutumia bei maalum"
Level: IMPORTANT
Buyer taps "Endelea Kulipa":
POST /checkout/initiate { offerId, quantity }
Spring Boot:
Validate: status=PENDING, not expired, buyer matches
Update status: CHECKOUT
Price from DB — never from client ✅
Return: { checkoutUrl, checkoutToken }
Order completes:
Update status: COMPLETED
order_id: linked
Send ORDER_CONFIRMATION stanza to conversation
Expiry fires (RabbitMQ delayed job):
Status still PENDING? → mark EXPIRED
Status already changed? → do nothing
Send OFFER_EXPIRED stanza to conversation
commerce_offer_sessions Table
commerce_offer_sessions
─────────────────────────────────────────────────────
offer_id UUID PK
conv_id UUID FK → conversations
message_id UUID FK → messages
shop_id UUID
buyer_id UUID
sent_by_staff UUID staff who sent (audit only)
product_id UUID
product_name TEXT
product_image_url TEXT
snapshot_json JSONB full product at offer time
public_price BIGINT TZS
offer_price BIGINT TZS (custom — server auth)
currency TEXT TZS
quantity_min INT
quantity_max INT
discount_amount BIGINT
discount_pct DECIMAL
status ENUM PENDING / ACCEPTED /
DECLINED / EXPIRED /
CHECKOUT / COMPLETED /
CANCELLED / ABANDONED
valid_minutes INT
expires_at TIMESTAMPTZ
initiated_by ENUM BUYER / SELLER
notes TEXT
created_at TIMESTAMPTZ
responded_at TIMESTAMPTZ
checkout_at TIMESTAMPTZ
completed_at TIMESTAMPTZ
order_id UUID FK → orders (after completion)
19. Build Order
NexGate chat is built from scratch — no migration, no Phase 1 to carry forward. This is the recommended sequence:
Week 1-2 — Local Experiments
Ejabberd running in Docker locally
Two containers (node1 + node2) clustered
Auth bridge: Spring Boot validates XMPP tokens
Send first message between two test JIDs
Confirm Erlang dist working between nodes
Confirm RabbitMQ events firing to Spring Boot
Week 3-4 — PostgreSQL Schema + Chat Service
All tables created (messages, conversations,
receipts, calls, offer sessions, reactions etc)
Spring Boot Chat Service:
RabbitMQ consumers for all Ejabberd events
Message persistence
Receipt tracking
Notification routing (FCM + Textfy)
Week 5 — Ejabberd Staging Deployment
Deploy to Hetzner staging VPS
Two node cluster live
Traefik sticky sessions configured
Auth bridge connected to Chat Service
Send first real message through staging Ejabberd
Week 6-7 — Mobile SDK + Basic Chat
NexGate Chat SDK (Android + iOS)
Smack / XMPPFramework wrapper
Clean send/receive API
Auto-reconnect + Stream Management
Text messages working end-to-end
Typing indicators
Delivery + read ticks
Presence (online/offline)
Week 8 — Message Interactions
Reactions (XEP-0444)
Edit messages (XEP-0308)
Delete for everyone (XEP-0424)
Forwarding (XEP-0297)
Replies (XEP-0461)
Week 9 — Voice Calls
TURN credentials endpoint in Spring Boot
Coturn deployed (Hetzner CX11)
Jingle signaling through Ejabberd
WebRTC on Android/iOS
Opus audio confirmed on 2G test
Coturn relay confirmed on EA network
Week 10 — Video Calls
H.264 video track added
Adaptive resolution ladder
Resolution ladder tested on 3G
Week 11 — Commerce DMs
Custom namespace stanzas:
PRODUCT_CARD
CUSTOM_PRICE_OFFER
OFFER_DECLINED / OFFER_EXPIRED
ORDER_CONFIRMATION
Offer session lifecycle
Both commerce flows (buyer initiates + seller attaches)
Checkout redirect flow
Shop inbox isolation + access control
Week 12 — Group Chats + Broadcast
MUC rooms (Ejabberd XEP-0045)
Group message reactions
Group typing indicators
Broadcast channels (read-only MUC)
Week 13 — Offline + Notifications
RabbitMQ offline queue
FCM HIGH priority integration
Textfy SMS escalation
Notification levels (NORMAL/IMPORTANT/CRITICAL)
Catch-up banner on reconnect
Week 14 — MessagePack
MessagePack encoding in SDK
Content-Type header detection in Ejabberd
Both JSON + MessagePack supported simultaneously
EA bandwidth savings confirmed
Week 15 — Testing + EA Network Testing
Test on actual Vodacom/Airtel SIM cards
Test on Tecno/Infinix devices
Test on 2G/3G networks
Call quality on Coturn relay confirmed
Commerce flow end-to-end confirmed
Week 16 — Ship 🚀
Production deployment
Two Ejabberd nodes live
All features confirmed
NexGate chat is live
Summary
NexGate chat is built directly on Phase 2 architecture from scratch. No migration. No legacy code. Greenfield build on carrier-grade infrastructure from day one.
Ejabberd Cluster (two Docker containers, same Hetzner VPS at launch) handles all WebSocket connections, XMPP stanza routing, presence, MUC group chats, Jingle voice/video signaling, and 25+ chat features via standard XEPs — all at zero custom code cost. Erlang Distribution connects the two nodes directly, routing messages between them in microseconds without Redis pub/sub.
Spring Boot Chat Service owns all business logic — message persistence, commerce context, offer session lifecycle, shop inbox access control, notification routing, and call records. It communicates with Ejabberd asynchronously via RabbitMQ for all events except auth, which is synchronous HTTP because Ejabberd needs an immediate allow/deny decision.
Custom XMPP Namespaces extend the protocol for NexGate's commerce features. Product cards, custom price offers, offer session responses, Bei ya pamoja cards, event cards, and post cards all travel as custom XML elements inside standard XMPP stanzas. Ejabberd routes them as-is — Spring Boot parses and handles them. Commerce messages are server-authoritative and immutable: offer prices come from the database, not the client. Public product prices are never touched.
WebRTC + Coturn handles voice and video calls. Jingle stanzas through Ejabberd coordinate setup. Opus adapts audio from 64kbps on WiFi to 6kbps on 2G. H.264 hardware acceleration keeps video calls battery-friendly on EA phones. Coturn relay ensures calls work behind EA carrier NAT on Vodacom, Airtel, and Tigo.
MessagePack reduces message frame size 60-65% — real saving for EA users on limited data bundles. Both JSON and MessagePack supported simultaneously during SDK rollout.
The build is 16 weeks from local experiments to production. WhatsApp-class infrastructure. Commerce-aware from day one. EA network optimized throughout.
NexGate Chat Platform — Phase 2: Production Architecture v1.0 QBIT SPARK | Ejabberd · Coturn · WebRTC · Commerce Stanzas · Edit · Delete · React · Forward
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