I Built an Authentication System With Express.js, MongoDB, (Access/Refresh Tokens, Sessions, Rate Limiting & More)

I recently finished building one of my most solid backend projects — a complete authentication system written in Express.js, powered by MongoDB, JWT, and a clean architecture design.

Here’s what I implemented step-by-step:

**🔐 Access + Refresh tokens with secure storage

🗂️ Session tracking in the database

🧹 Automatic session invalidation

🛡️ IP-based rate limiting (5 attempts / 10 mins)

🧪 Validation middleware for all inputs

⚠️ Global ApiError system for consistent error formatting

🧱 Clean architecture with controllers, services, utils

🛠️ Multiple bug fixes + edge case handling

🚀 Focus on maintainability & production readiness**

This project taught me a LOT about system design, real-world auth, and secure backend development.

If you like it, Hit a ⭐ on GitHub or share it with other developers!

👉 GitHub Repo: https://github.com/hamidukarimi/authforge-express
If you have ideas on improvements or want the front-end version too — let me know!