JustAPI Documentation
Welcome to the official documentation for JustAPI, a high-performance Python web framework built on top of a powerful Rust core.
JustAPI is designed to be a drop-in replacement for FastAPI but engineered to handle extreme throughput—achieving up to 700k Requests Per Second (RPS) without breaking a sweat.
Why JustAPI?
🚀 Rust Core Performance
The entire HTTP server, routing engine, and protocol parsing are written in Rust using highly optimized crates like tokio and hyper. This ensures that connection handling is as fast and secure as theoretically possible.
🐍 Python Ergonomics
You get the raw performance of Rust with the beautiful, developer-friendly ergonomics of Python. You write standard Python using familiar concepts like JustAPIApp, @app.get, and Pydantic schemas for data validation.
⚡ Zero-Copy Architecture
JustAPI uses a highly optimized boundary between Rust and Python (via PyO3). By implementing the Python Buffer Protocol, the framework avoids unnecessary memory allocations and copies, making it incredibly memory-efficient.
🔄 100% Async
Built entirely on async/await principles. JustAPI seamlessly bridges Rust's Tokio runtime with Python's native asyncio event loop.
Performance Matrix
JustAPI obliterates traditional frameworks under load. Measured on an Intel Core i5-13600K against the Uvicorn+FastAPI baseline:
| Metric / Workload | Uvicorn + FastAPI | JustAPI (Native Python) | Improvement |
|---|---|---|---|
| Hello-World (GET) throughput | 36,189 req/sec | 324,130 req/sec | ~9x Faster |
| Hello-World (GET) p99 latency | 24.63 ms | 1.10 ms | ~22x Lower |
| JSON-Echo (POST) throughput | 26,000 req/sec | 267,846 req/sec | ~10x Faster |
| JSON-Echo (POST) p99 latency | 14.50 ms | 1.64 ms | ~9x Lower |
(Note: JustAPI achieves these numbers in a single process without multi-worker fan-out.)
Master Developer Handbook
For a comprehensive end-to-end tutorial, architecture deep-dive, database guides, and production deployment handbook:
👉 Read the JustAPI Developer Handbook (HANDBOOK.md)
Where to go next?
- Developer Handbook: Complete end-to-end tutorial & master reference.
- Getting Started: Build your first JustAPI application in minutes.
- Migrating from FastAPI: See how easy it is to switch your existing FastAPI project to JustAPI.
- API Reference: Detailed documentation of classes, functions, and kwargs.
- Plugins: Learn how to extend JustAPI using Python or Rust WASM plugins.