asgi-ratelimiter

Fixed-window rate limiting for ASGI apps. Use Depends with FastAPI or middleware with Starlette.

SQLite by default · Redis optional · Typed · Python 3.14+

Install

pip install "asgi-ratelimiter[fastapi]"           # FastAPI + SQLite
pip install "asgi-ratelimiter[fastapi,redis]"     # FastAPI + Redis
pip install "asgi-ratelimiter[starlette,redis]"   # Starlette + Redis

Or with uv: uv add "asgi-ratelimiter[fastapi]".

Quick start

Define a rate:

from asgi_ratelimiter import Duration, Rate

rate = Rate(limit=5, interval=Duration.MINUTE)  # 5 / min
rate = Rate(limit=100, interval=Duration.HOUR * 2)  # 100 / 2h

FastAPI

from fastapi import Depends, FastAPI
from asgi_ratelimiter import Duration, Rate
from asgi_ratelimiter.fastapi import RateLimiter

app = FastAPI(
	dependencies=[Depends(RateLimiter(rate=Rate(limit=5, interval=Duration.MINUTE)))]
)


@app.get("/ping")
async def ping():
	return {"ok": True}

Over limit → 429 + Retry-After.

Starlette

from starlette.applications import Starlette
from starlette.responses import PlainTextResponse
from starlette.routing import Route
from asgi_ratelimiter import Duration, Rate
from asgi_ratelimiter.starlette import RateLimitMiddleware


async def homepage(request):
	return PlainTextResponse("ok")


app = Starlette(routes=[Route("/", homepage)])
app.add_middleware(
	RateLimitMiddleware,
	rate=Rate(limit=5, interval=Duration.MINUTE),
)

Redis

from redis.asyncio import Redis
from asgi_ratelimiter import Duration, Rate
from asgi_ratelimiter.backends.redis import RedisBackend
from asgi_ratelimiter.fastapi import RateLimiter

redis = Redis.from_url("redis://localhost:6379/0")
limiter = RateLimiter(
	rate=Rate(limit=5, interval=Duration.MINUTE),
	backend=RedisBackend(redis=redis),
)

Same backend= pattern works with Starlette middleware.

Logging

from asgi_ratelimiter import configure_logging, set_level

configure_logging(level="DEBUG")
set_level("WARNING")

Off until you call configure_logging / set_level (loguru).

Examples

uv sync --group dev
uv run --with "uvicorn[standard]" python examples/fastapi/fastapi_sqlite.py

Development

uv sync --group dev
uv run pytest
uv run ruff check .
uv run ruff format .

See CONTRIBUTING.md and AGENTS.md.

License

AGPL-3.0-or-later · Changelog · Issues