ASP.NET Core Web API Interview Question #140

What is HTTP 429 Too Many Requests?

Error Handling, Logging, Caching, Rate Limiting, CORS & Reliability Senior Advanced

Quick Interview Answer

429 Too Many Requests indicates that a client has exceeded an applicable request limit. A rate-limited API may also provide retry information such as a Retry-After header when the policy can determine an appropriate delay.

Detailed Explanation

429 Too Many Requests indicates that a client has exceeded an applicable request limit. A rate-limited API may also provide retry information such as a Retry-After header when the policy can determine an appropriate delay.

Clients should handle 429 deliberately rather than immediately retrying in a tight loop.

Code Example

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

{
  "title": "Rate limit exceeded",
  "status": 429
}