asgi-ratelimiter

Modular rate limiting for ASGI apps — use Depends with FastAPI or middleware with Starlette.

Fixed-window limits backed by SQLite (stdlib). Redis extra is reserved for later.

Requirements

• Python 3.14+

Install

# FastAPI (SQLite backend is built-in)
uv add "asgi-ratelimiter[fastapi]"

# Starlette
uv add "asgi-ratelimiter[starlette]"

Extras:

Combine extras: uv add "asgi-ratelimiter[fastapi,sqlite]".

Concepts

from asgi_ratelimiter import Duration, Rate

# Allow 10 calls every 5 minutes
rate = Rate(limit=10, interval=Duration.MINUTE * 5)

Duration units: SECOND, MINUTE, HOUR, DAY, WEEK (multiply for longer windows).

FastAPI

App-wide or per-route via Depends(RateLimiter(...)):

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

configure_logging(level="INFO")

limiter = RateLimiter(
    rate=Rate(limit=5, interval=Duration.MINUTE),
    identifier=lambda request: request.client.host if request.client else "default",
    db_path="rate_limits.db",
)

app = FastAPI(dependencies=[Depends(limiter)])

@app.get("/ping")
async def ping() -> dict[str, str]:
    return {"status": "ok"}

Over limit → HTTP 429 with optional Retry-After.

Runnable example: examples/fastapi/fastapi_sqlite.py

Starlette

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

configure_logging(level="INFO")

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

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

Runnable example: examples/starlette/starlette_sqlite.py

Logging

from asgi_ratelimiter import configure_logging, set_level

configure_logging(level="DEBUG")  # enable library logs (loguru)
set_level("WARNING")              # change level later

Logging is off until configure_logging (or set_level) is called.

Development

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

See CONTRIBUTING.md.

License

AGPL-3.0-or-later

Links

• Repository: https://github.com/luisgcss/asgi-ratelimiter
• Issues: https://github.com/luisgcss/asgi-ratelimiter/issues
• Changelog: CHANGELOG.md