Helix Exchange

Production-grade mini exchange monorepo. NestJS API, Typescript matching engine, NATS JetStream, PostgreSQL, Prisma.

Prerequisites

• Node.js 20+
• pnpm 8+
• Docker (for Postgres + NATS)

Quick Start

1. Copy environment:

   cp .env.example .env
   cp .env.example apps/api/.env

2. Start infrastructure (Postgres, NATS):

   make up

3. Create NATS JetStream streams (orders.commands., orders.events., trades.events.*):

   make nats-setup

4. Install dependencies and run migrations:

   pnpm install
   make migrate

5. Run services locally:

   make api      # NestJS API on http://localhost:3000
   make engine   # Go matching engine

Structure

helix-exchange/
├── apps/
│   ├── api/          # NestJS REST API
│   └── engine/       # Go matching engine
├── packages/
│   └── contracts/    # Shared event types (TypeScript)
└── infra/
    └── docker-compose.yml

Environment

Variable	Description	Default
PORT	API server port	3000
DATABASE_URL	PostgreSQL connection	postgresql://...
NATS_URL	NATS server URL	nats://localhost:4222
NATS_MAX_RECONNECT	NATS reconnect attempts	10

Development

• API: make api or pnpm --filter api dev
• Database migrations: make migrate
• Docker logs: make logs

Docker

Command	Description
make up	Start Postgres, NATS, API, Engine
make down	Stop all containers
make logs	Tail container logs

Ports

Service	Port
API	3000
Postgres	5432
NATS	4222

Health Check

• API: GET http://localhost:3000
• Health: GET http://localhost:3000/health