Messaging App API

Frontend Repo (Vite, React, TS)

Live Demo

REST API backend for a real-time messaging application. Handles user authentication, friend requests, conversations, and message delivery. The frontend is a separate Vite + React + TypeScript app.

Tech Stack

• Runtime: Bun. Originally written for Node.js, migrated to the Bun runtime with minimal changes. It is still a standard Express.js app.
• Framework: Express.js
• Database: MongoDB via Mongoose
• Real-time: Socket.IO used for live message delivery between connected clients
• Authentication: JWT bearer tokens. Protected routes require a valid Authorization: Bearer <token> header.
• Validation: Zod schemas applied via Express middleware on all incoming request bodies and params
• Testing: Bun's built-in test runner with Supertest and mongodb-memory-server for in-process integration tests. Originally used Jest, replaced with bun:test later. Bun's test runner is Jest-compatible.

Features

• User registration and login
• Friend request system
• One-on-one conversations between users
• Paginated message history
• Real-time messaging via Socket.IO rooms

Deployment

Containerized with Docker. A multi-stage Dockerfile compiles the app into a single self-contained executable using bun build --compile. Docker BuildKit secrets are used to inject environment variables at build time without leaking them into image layers.

The live demo runs on a Hetzner VPS.

Local development

bun run dev

Local build (single-file executable)

bun run build
bun run start

Docker

bun run docker:build
bun run docker:run

Tests

bun test
bun test --watch