HTTP 429 Too Many Requests

What does HTTP 429 mean?

The client sent too many requests in a given amount of time. Rate limiting. The response may include Retry-After (seconds or a date) and headers such as RateLimit-Remaining. Bot protection and APIs use 429 heavily.

4xx Client error: The request has a problem the client can fix: wrong URL, missing credentials, bad data or too many requests.

Common causes of a 429 error

• Exceeding an API’s rate limit.
• Aggressive crawling or scraping.
• Shared IP addresses (offices, VPNs, cloud hosts) hitting a per-IP limit.

How to fix 429 Too Many Requests

• Respect Retry-After and use exponential backoff.
• Cache responses and batch requests.
• As a site owner, exempt verified search-engine crawlers from strict limits.

429 and SEO

Googlebot slows down when it receives 429s. Short bursts are fine; sustained 429s reduce crawling and can drop pages from the index.

Example response

HTTP/1.1 429 Too Many Requests
Retry-After: 60
RateLimit-Remaining: 0

How to return a 429 response

Node.js (Express)

res.status(429).json({ error: 'Too Many Requests' });

PHP

http_response_code(429);

Python (Flask)

return {'error': 'Too Many Requests'}, 429

Go (net/http)

w.WriteHeader(429)

nginx

return 429;

Related status codes

• 503 Service Unavailable — The server is temporarily unable to handle the request.
• 403 Forbidden — The server understood the request but refuses to authorize it.

Check which status code a URL returns with the HTTP header checker.