The speed of Rust.
The elegance of Python.
JustAPI is a drop-in replacement for FastAPI engineered for extreme throughput. Achieve up to 9x the throughput and 22x lower tail latency.
main.py
from justapi import JustAPIApp
app = JustAPIApp()
@app.get("/")
async def hello():
return {"message": "324k RPS, easily."}
if __name__ == "__main__":
app.run("127.0.0.1:8000")Why JustAPI?
Rust Core
The entire HTTP server, routing, and protocol parsing is written in Rust using Tokio and Hyper.
Python Ergonomics
Write standard Python using familiar concepts. It's designed as a drop-in replacement for FastAPI.
Zero-Copy
Avoids unnecessary allocations between Rust and Python, making it incredibly memory-efficient.
100% Async
Exposes native Python asyncio boundaries tightly integrated with the underlying Rust event loop.
Performance Matrix
JustAPI crushes traditional frameworks under load. Measured on an Intel Core i5-13600K.
| Metric / Workload | Uvicorn + FastAPI | JustAPI (Native Python) | Improvement |
|---|---|---|---|
| Hello-World (GET) - Throughput | 36,189 req/sec | 324,130 req/sec | ~9.0x Faster |
| Hello-World (GET) - p99 Latency | 24.63 ms | 1.10 ms | ~22.4x Lower |
| JSON-Echo (POST) - Throughput | 26,000 req/sec | 267,846 req/sec | ~10.3x Faster |
| JSON-Echo (POST) - p99 Latency | 14.50 ms | 1.64 ms | ~8.8x Lower |