Live Coding Interview - Money Transfer API

Given:

• A prebuilt Node.js + TypeScript project inside a Docker container.
• A predefined PostgreSQL database.
• The database is configured via Docker Compose.
• Node.js, TypeScript, and the pg driver are already installed.
• You are free to install and use any framework (Express, etc.) and ORM/query builder (TypeORM, raw SQL, etc.) of your choice.
• Models, routes, and server need to be implemented.

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Getting Started

docker-compose up --build

The API server will be available at http://localhost:8000. File changes are automatically reloaded.

Database connection is available via environment variables: DB_HOST, DB_PORT, DB_NAME, DB_USER, DB_PASSWORD.

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Task

Create an API endpoint for handling money transfers between users.

Expected Success Response

{
  "message": "Transaction successful",
  "sender": {"id": 1, "username": "Alice", "balance": 800.00},
  "receiver": {"id": 2, "username": "Bob", "balance": 1200.00}
}

Expected Failure Response

{
  "error": "Proper error message here..."
}