Retry-After header in Rest API - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the Retry-After header in HTTP?

The Retry-After header tells the client how long to wait before making another request. It helps manage server load and avoid repeated requests during downtime or rate limiting.

beginner

What are the two formats allowed for the Retry-After header value?

The Retry-After header value can be either:<br>1. A number representing seconds to wait.<br>2. An HTTP-date indicating the exact time after which to retry.

beginner

When is the Retry-After header typically used in HTTP responses?

It is commonly used with status codes 429 Too Many Requests and 503 Service Unavailable to tell clients when to retry their requests.

beginner

Example: What does this header mean?<br>Retry-After: 120

It means the client should wait 120 seconds (2 minutes) before retrying the request.

beginner

Example: What does this header mean?<br>Retry-After: Wed, 21 Oct 2024 07:28:00 GMT

It means the client should wait until the date and time Wed, 21 Oct 2024 07:28:00 GMT before retrying the request.

What does the Retry-After header tell the client?

A The type of content returned

B The size of the response body

C How long to wait before retrying a request

D The server's IP address

The Retry-After header tells the client how long to wait before retrying the request.

Which HTTP status code commonly uses the Retry-After header?

A 404 Not Found

B 301 Moved Permanently

C 200 OK

D 429 Too Many Requests

The Retry-After header is commonly used with 429 Too Many Requests to tell clients when to retry.

Which of these is NOT a valid format for the Retry-After header value?

A A URL to retry

B HTTP-date format

C Number of seconds to wait

D None of the above

The Retry-After header value must be seconds or a date, not a URL.

If a server responds with Retry-After: 60, what should the client do?

A Wait 60 seconds before retrying

B Retry immediately

C Ignore the header

D Retry after 60 minutes

The client should wait 60 seconds before retrying the request.

The Retry-After header helps to:

A Increase the speed of requests

B Reduce server overload by controlling retry timing

C Change the request method

D Encrypt the response

It helps reduce server overload by telling clients when to retry.

Explain what the Retry-After header is and when it is used.

Think about how servers tell clients to pause before retrying.

Describe the two formats allowed for the Retry-After header value and give an example of each.

One is a number, the other is a date string.