fastapi-easylimiter 0.4.1

Async rate limiter for FastAPI with Redis or in-memory backend and advanced proxy-aware security

fastapi‑easylimiter

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An ASGI async rate-limiting middleware for FastAPI with Redis, designed to handle auto-generated routes (e.g., FastAPI-Users) without decorators, for simplicity and ease of use.

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Features

• Path based rules (/api/*, /auth/*, exact matches)
• Fixed & sliding window algorithms (Lua)
• RateLimit, RateLimit-Policy, Retry-After headers
• Bans with back-off per IP with configurable window
• BaseHTTPMiddleware for FastAPI/Starlette
• Async Redis support
• Easy to configure
• No decorators needed
• HTML/JSON error responses

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TODO

• In-memory option
• Additional strategies

Installation

pip install fastapi-easylimiter

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Usage

from fastapi import FastAPI
import redis.asyncio as redis
from middleware.rate import RateLimitMiddleware

app = FastAPI()

redis_client = redis.from_url("redis://localhost:6379/0")

app.add_middleware(
    RateLimitMiddleware,
    redis=redis,
    rules={
        "/*": (200, 60, "fixed"),           
        "/api/*": (5, 1000, "sliding"),
        "/api/auth/*": (3, 1, "sliding"),
        "/api/users/me": (2, 30, "fixed"),
    },
    exempt=[],
    enable_bans=True,
    ban_offenses=8,
    ban_window="10m",
    ban_length="5m",
    ban_max_length="1d",
    )

Example: /api/auth/login matches /api/auth and /api. If any rule is exceeded → 429 returned. If banned → 403 returned.

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Redis Key Patterns

Key Pattern	Example	Type	Used For
rl:Fixe:{hash}:{limit}:{window}	rl:Fixe:a1b2c3d4e5f6a7b8:100:60	String	Fixed-window counter
rl:Slid:{hash}:{limit}:{window}	rl:Slid:a1b2c3d4e5f6a7b8:60:60	ZSET	Sliding window request log
offense:{identifier}	offense:203.0.113.5	ZSET	Offense tracking for ban escalation
ban:{identifier}	ban:203.0.113.5	String+TTL	Active ban flag

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Middleware Parameters

Parameter	Type	Required	Description
redis	redis.asyncio.Redis	Yes	Redis async client
rules	Dict[str, Tuple[int, int, str]]	Yes	Path → (limit, period, strategy)
exempt	Optional[List[str]]	No	Paths that bypass rate limits
enable_bans	bool	No	Enable/disable ban system
ban_offenses	int	No	Offenses before ban triggers
ban_window	str	No	Time window for offense accumulation
ban_length	str	No	Initial ban length
ban_max_length	str	No	Maximum exponential ban ceiling

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Screenshot

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Contributing

Contributions and forks are always welcome! Adapt, improve, or extend for your own needs.

Support

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