Rate limits, 429 and Retry-After

Bound resource use and guide clients.

UnderstandStudy an examplePractise

Understand the concept

Limits can use account, IP, API key or operation cost. IP-only policies can penalise shared networks; trusting forged forwarding fields undermines counters. Login, uploads and AI requests have different costs.

429 communicates limiting. Retry-After can be seconds or an HTTP-date, so parse deliberately. Bound retries with backoff, jitter and a total deadline.

Connections and large bodies can consume resources independently of request count. Combine limits with bounded queues, concurrency controls and monitoring. Example limits are illustrative, not production capacity recommendations.

WHEN TO USE IT

Protect expensive AI and contact-form endpoints.

COMMON PITFALL

Immediately retrying a 429 indefinitely.

01 / PRACTICE

One topic. Three levels of depth.

HTTP / illustrative example

HTTP/1.1 429 Too Many Requests
Retry-After: 30

An advisory thirty-second delay.

This page does not send requests to external servers. Messages are readable HTTP/1.1 illustrations, not HTTP/2 or HTTP/3 wire dumps. example.test is reserved for examples. Run commands and JavaScript only in your own test environment; never publish real tokens or cookies.

02 / YOUR TURN

Try it yourself first.

Is Retry-After always an integer?

Show the solution and explanation

Worked solution

delay-seconds OR HTTP-date

No; it can be an HTTP-date.

RasimAtaberkŞahin

Understand the concept

One topic. Three levels of depth.

Try it yourself first.