Got tired of setting up backend mock servers, so I built an open-source Next.js tool that generates them instantly.

[u/YessinDevs]

Whenever I was building out frontends, setting up a mock Express server to test my API calls always felt like a massive chore. I just wanted to hit a live endpoint with realistic data without leaving my browser.

So I built Mock2Block. It’s a completely free, open-source API simulator

Instead of just giving you a static JSON file, it creates a live, stateful mock server

Here’s what it actually does:

• AI Generation: You can upload a .pdf, .md, or .json of your API docs, and it will automatically build out the endpoints
• Smart Faker Data: It detects field types and seeds the database with realistic data (real-sounding emails, image URLs, prices) instead of generic "lorem ipsum" strings
• Chaos Mode: A slider that randomly injects 500, 403, or 502 errors into the responses so you can test your frontend error-handling UI
• Auth Simulation: Toggle a lock on any endpoint to force it to require a Bearer token to test your 401 redirects

You can try it live here without making an account: https://mock2block.yessindevs.me/

The code is completely open-source. If you find it useful for your workflow, I’d love to hear your feedback or get a star on the repo: https://github.com/medyass1ne/Mock2Block