What it means
The client sent too many requests in a given time (rate limiting). Retry-After may say how long to wait.
Common causes
- Exceeded API rate limits or quotas
- Retry loops without backoff
- Many users behind one shared IP
How to fix it
As a client or visitor
Respect Retry-After, use exponential backoff with jitter, cache results and batch requests.
As the site or API owner
Return Retry-After and RateLimit headers so clients can adapt, and limit per key or user rather than only per IP.
Example response
HTTP/1.1
HTTP/1.1 429 Too Many Requests
Date: Tue, 07 Oct 2025 09:30:00 GMT
Server: nginx
Retry-After: 30
RateLimit-Policy: 100;w=60
Content-Type: application/problem+json
{
"type": "about:blank",
"title": "Too Many Requests",
"status": 429,
"detail": "Rate limit of 100 requests per minute exceeded."
}Specification
FAQ
› How long should I wait after a 429?
Use Retry-After if present; otherwise back off exponentially, for example 1, 2, 4, 8 seconds with random jitter.
› Does 429 hurt SEO?
Googlebot slows crawling when it sees 429. Short spells are fine; long ones can delay indexing.