Internal Transfers System

This system handles account creation, balance queries, and financial transactions with a focus on data integrity, consistency, and financial accuracy.

Technology Stack

• Language: Go 1.22+
• HTTP Router: Chi
• Database: PostgreSQL 16
• Database Driver: pgx v5
• Migrations: golang-migrate
• Logging: slog (Go standard library)
• Containerization: Docker & Docker Compose

Prerequisites

• Docker & Docker Compose - Install Docker

Run the application server

Using Docker Compose

# Clone the repository
git clone <repository-url>
cd internal-transfer

# Create a .env file based on the example
cp .env.example .env

# Start all services (PostgreSQL + API)
make docker-up

# The API will be available at http://localhost:8080
# Test the health endpoint
curl http://localhost:8080/health

Configuration

The project uses a .env file for configuration. A default file is created during setup, or you can create one manually:

cp .env.example .env

Ensure your .env contains:

DB_HOST=postgres or 'localhost' if running locally
DB_PORT=5432
DB_USER=postgres
DB_PASSWORD=postgres
DB_NAME=transfers
DB_SSL_MODE=disable
SERVER_PORT=8080
SERVER_HOST=0.0.0.0
LOG_LEVEL=info

Assumptions

1. Single Currency: All accounts use the same currency
2. User-Provided IDs: Account IDs are provided by clients (not auto-generated)
3. Decimal Precision: Supports up to 18 decimal places (sufficient for cryptocurrency)
4. No Authentication: Authentication/authorization is handled by API gateway
5. Synchronous Processing: Transfers are processed synchronously