Architecture · ops.tradeit.gg

Backend Services Deep Dive

Deep dive into each core backend service — purpose, major components, connections, and key details.

Last updated: 2026-05-09

tradeit-backend

The heart of the platform. Handles all user-facing API endpoints, trade lifecycle, inventory queries, pricing reads, and bot coordination.

Major Components

• Routes: Express route files organized by domain (trades, inventory, users, deposits, withdrawals)
• OpenSearch integration: openSearchService.js — inventory search with reserved item exclusion (genMustNot, mustNotGroup patterns)
• Bull queues: Async job processing for trades, notifications
• Transaction context: express-http-context for request-scoped state
• MySQL pools: 40 connections, named placeholders, BigNumber as strings
• dd-trace: Datadog APM (must be imported first — before all other modules)

Connections

graph LR
    BE[tradeit-backend] --> MySQL[(MySQL Aurora)]
    BE --> Redis[(Redis)]
    BE --> OS[(OpenSearch)]
    BE --> TBS[tradeit-tradebot-server]
    BE --> SS[tradeit-socket-server]
    BE --> LS[tradeit-login-server]
    NT[new-tradeit] --> BE
    ADM[tradeit-admin-backend] --> BE

Key Details

• Port: 3000
• PM2 cluster mode inside Docker (--read-only, no curl)
• Webpack bundled for production
• Site disable toggle via config
• 429 rate limit interceptor

tradeit-tradebot-server

📖 Full deep dive: tradeit-tradebot-server — Redis/Bull contract surface, trade lifecycle sequences, MySQL surface, auto-QA contract.

Manages the entire fleet of ~400 Steam trade bots. Executes trades, monitors bot health, handles Steam API interactions.

Major Components

• Bot process: Single large file per bot instance — handles trade offers, inventory, health
• Redis pub/sub: Communicates with tradeit-backend for trade coordination
• Bull queues: Trade execution pipeline
• Steam SDK stack: steam-user, steam-tradeoffer-manager, steam-community
• Casket system: Manages storage containers for bot items
• Login rate limiter: Prevents Steam API bans

Connections

graph LR
    BE[tradeit-backend] --> TBS[tradeit-tradebot-server]
    TBS --> Steam[Steam API]
    TBS --> Redis[(Redis)]
    TBS --> MySQL[(MySQL)]
    IS[tradeit-inventory-server] --> TBS

Key Details

• Bot tiers: veryGoodBots > goodBots > badBots (withdrawal routing priority)
• allowedPartnerIds: Whitelist for trusted trade partners
• Trade types: deposit, withdrawal, player-to-player
• Bots spread across multiple EC2 instances
• Restart via SSH scripts to EC2

tradeit-inventory-server

Fetches and aggregates bot inventories from Steam. Two sub-services: sinvbot (site inventory) and cinvbot (user/container inventory).

Major Components

• sinvbot (port 3000): Aggregates all bot inventories into site-wide view, fork mode
• cinvbot (port 3001): Fetches individual user/bot inventories, 4x cluster mode
• Bull queues: IP rotation, coordinated bot inventory fetching
• Redis as data bus: Compressed single-letter property names for payload efficiency
• PM2 instance 0: Special behavior — runs as queue processor

Connections

graph LR
    IS[tradeit-inventory-server] --> Steam[Steam API]
    IS --> Redis[(Redis)]
    IS --> MySQL[(MySQL)]
    IS --> ScraperAPI["ScraperAPI
fallback"]
    BE[tradeit-backend] --> IS
    IP[tradeit-inventory-parser] --> IS

Key Details

• Flat file structure (no src/): sinvbot.ts, cinvbot.ts, util.ts
• Compressed property names (e.g., single-letter keys) for Redis payload size
• Express 5, legacy mysql driver (not mysql2)
• Deploy via Makefile + deploy.sh to EC2

tradeit-socket-server

Real-time WebSocket server. Pushes live updates to the frontend for inventory changes, trade status, and leaderboard.

Major Components

• Socket.IO 4: Main WebSocket engine with Redis adapter
• Redis pub/sub: Receives events from tradeit-backend
• MySQL polling: Falls back to polling for data that lacks pub/sub events (500ms interval)
• Throttled events: Reserve/unreserve events throttled to prevent client overload

Connections

graph LR
    SS[tradeit-socket-server] --> Redis[(Redis)]
    SS --> MySQL[(MySQL)]
    BE[tradeit-backend] -->|pub/sub| SS
    SS -->|WebSocket| NT[new-tradeit]

Key Details

• Port: 3000
• No PM2 in production (single process)
• 3-file src/ layout
• Legacy mysql driver

tradeit-service

Secondary API service. Handles SIH (Steam Inventory Helper) exports, product feed generation, and scheduled data processing jobs.

Major Components

• API endpoints: SIH feed, product feed exports, item data endpoints
• Scheduled jobs: Cron-based data aggregation and file generation
• OpenSearch: Scroll pagination for large dataset exports
• File-based data exchange: Generates files consumed by other services

Connections

graph LR
    SVC[tradeit-service] --> MySQL[(MySQL)]
    SVC --> OS[(OpenSearch)]
    SVC --> Redis[(Redis)]
    BE[tradeit-backend] --> SVC

Key Details

• Port: 3001
• No src/ directory — files at root
• Singleton pattern for service instances
• Ramda utility usage
• Staging index suffix for env separation

tradeit-login-server

Steam authentication service. Handles Steam OpenID login flow, session creation, and domain validation.

Major Components

• Steam OpenID: Passport.js with forked passport-openid strategy
• Domain whitelist: Validates redirect URLs against allowed domains
• Redis sessions: Session store with configurable TTL

Connections

graph LR
    LS[tradeit-login-server] --> Steam[Steam OpenID]
    LS --> Redis[(Redis)]
    NT[new-tradeit] --> LS
    LS --> BE[tradeit-backend]

Key Details

• Port: 3000
• Single-file architecture (login.ts)
• Express 5 with forked passport library (compiled JS checked into repo)
• Domain whitelist for redirect validation

tradeit-oauth2-server

OAuth2/OIDC authentication server. Supports Steam, FACEIT, and GitHub login strategies with Swagger API documentation.

Major Components

• Passport strategies: Steam, FACEIT, GitHub
• Swagger: Auto-generated API documentation
• TypeORM: User and client management
• JWT: Token-based authentication

Connections

graph LR
    OA[tradeit-oauth2-server] --> MySQL[(MySQL)]
    OA --> Steam[Steam API]
    OA --> FACEIT[FACEIT API]
    OA --> GitHub[GitHub API]
    BE[tradeit-backend] --> OA

Key Details

• Port: 3000
• Docker image name mismatch: Makefile uses tradeit-oauth-server vs deploy.sh uses tradeit-oauth2-server
• NestJS with TypeORM

tradeit-admin-backend

Admin panel API. Powers the internal admin dashboard for managing items, users, bots, and pricing overrides.

Major Components

• Dual Prisma schemas: Main DB + Pricing DB
• JWT auth: Role-based access (admin hierarchy)
• Express routes: CRUD for all admin operations
• BigInt serialization: Custom JSON serializer for MySQL BigInt columns

Connections

graph LR
    AB[tradeit-admin-backend] --> MySQL[(MySQL)]
    ADM[tradeit-admin] --> AB
    AB --> BE[tradeit-backend]

Key Details

• Port: 3000
• Express (not NestJS), Prisma (not TypeORM)
• PM2 cluster mode
• Conditional JSON parsing middleware
• dotenv import ordering matters

Related Pages

• System Architecture — Full system diagram and data stores
• Microservices & Repos — Service catalog
• Pricing Pipeline — How prices flow
• Trade Lifecycle — How trades execute

ops.tradeit.gg — Internal Engineering Docs