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Rate-limiting for the requests library

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This package is a thin wrapper around pyrate-limiter that adds convenient integration with the requests library.

Project documentation can be found at


  • pyrate-limiter implements the leaky bucket algorithm, supports multiple rate limits, and optional persistence with SQLite and Redis backends
  • requests-ratelimiter can be used as a transport adapter, session, or session mixin for compatibility with other requests-based libraries.
  • Rate limits can be automatically tracked separately per host, and different rate limits can be manually applied to different hosts


pip install requests-ratelimiter



Example with LimiterSession:

from requests import Session
from requests_ratelimiter import LimiterSession

# Apply a rate-limit (5 requests per second) to all requests
session = LimiterSession(per_second=5)

# Make rate-limited requests that stay within 5 requests per second
for _ in range(10):
    response = session.get('')


Example with LimiterAdapter:

from requests import Session
from requests_ratelimiter import LimiterAdapter

session = Session()

# Apply a rate-limit (5 requests per second) to all requests
adapter = LimiterAdapter(per_second=5)
session.mount('http://', adapter)
session.mount('https://', adapter)

# Make rate-limited requests
for user_id in range(100):
    response = session.get(f'{user_id}')

Per-Host Rate Limits

With LimiterAdapter, you can apply different rate limits to different hosts or URLs:

# Apply different rate limits (2/second and 100/minute) to a specific host
adapter_2 = LimiterAdapter(per_second=2, per_minute=100)
session.mount('', adapter_2)

Behavior for matching requests is the same as other transport adapters: requests will use the adapter with the most specific (i.e., longest) URL prefix for a given request. For example:

session.mount('', adapter_3)
session.mount('', adapter_4)

# This request will use adapter_3

# This request will use adapter_4

Per-Host Rate Limit Tracking

With either LimiterSession or LimiterAdapter, you can automatically track rate limits separately for each host; in other words, requests sent to one host will not count against the rate limit for any other hosts. This can be enabled with the per_host option:

session = LimiterSession(per_second=5, per_host=True)

# Make requests for two different hosts
for _ in range(10):
    response = session.get(f'')

Server-Side Rate Limit Behavior

Sometimes, server-side rate limiting may not behave exactly as documented (or may not be documented at all). Or you might encounter other scenarios where your client-side limit gets out of sync with the server-side limit. In most cases, a server will send a 429: Too Many Requests response for an exceeded rate limit.

requests-ratelimiter will handle this by setting the local limit tracker to a "limit exceeded" state. If a server sends a different status code to indicate an exceeded limit, you can set this via limit_statuses:

session = LimiterSession(per_second=5, limit_statuses=[429, 500])

Or if you would prefer to disable this behavior and handle it yourself:

session = LimiterSession(per_second=5, limit_statuses=[])


By default, rate limits are tracked in memory and are not persistent. You can optionally use either SQLite or Redis to persist rate limits across threads, processes, and/or application restarts. See pyrate-limiter docs for more details.


There are many other useful libraries out there that add features to requests, most commonly by extending or modifying requests.Session or requests.HTTPAdapter.

To use requests-ratelimiter with one of these libraries, you have a few different options:

  1. If the library provides a custom Session class, mount a LimiterAdapter on it
  2. Or use LimiterMixin to create a custom Session class with features from both libraries
  3. If the library provides a custom Adapter class, use LimiterMixin to create a custom Adapter class with features from both libraries

Custom Session Example: Requests-Cache

For example, to combine with requests-cache, which also includes a separate mixin class:

from pyrate_limiter import RedisBucket
from requests import Session
from requests_cache import CacheMixin, RedisCache
from requests_ratelimiter import LimiterMixin

class CachedLimiterSession(CacheMixin, LimiterMixin, Session):
    """Session class with caching and rate-limiting behavior. Accepts arguments for both
    LimiterSession and CachedSession.

# Optionally use Redis as both the bucket backend and the cache backend
session = CachedLimiterSession(

This example has an extra benefit: cache hits won't count against your rate limit!

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