4xx Client error
HTTP 429 Too Many Requests
The client has sent too many requests in a given amount of time: it is being rate limited. The response should explain the limit and may say how long to wait in a Retry-After header.
Defined in RFC 6585, section 4(opens in a new tab)
//_01 Uptime checks
Is 429 up or down for a monitor?
Uptimecheck HTTP monitor
Default settings
Down. It is outside the default 200–399 range, so a monitor reports an outage once a second check confirms it. If 429 is the answer you expect from that URL, add it to the monitor’s expected status codes.
Is it down? checker
Free, at /is-it-down/
Up. The checker counts any answer below 500 as the site answering: a 429 comes from a server that is running.
//_02 Causes and fixes
Why you see 429 and what to do
Typical causes
- API rate limits, or rate-limiting rules at a firewall or CDN.
- Bots, scrapers or a script retrying too fast.
- Many users behind one address (an office, a mobile network) counted as one client, or a rate limiter that sees the proxy’s address instead of the visitor’s.
If you run the site
- Send Retry-After and say what the limit is.
- Make sure the rate limiter sees the real client address when the site is behind a CDN or load balancer.
- Exempt your health checks and uptime monitoring, or they report your own limit as downtime.
If you’re a visitor
- Wait a minute and try again, more slowly.
- If it keeps happening, try another network; you may share an address with someone sending a lot of requests.
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Questions
What does HTTP 429 mean?
The client has sent too many requests in a given amount of time: it is being rate limited. The response should explain the limit and may say how long to wait in a Retry-After header.
Does an uptime monitor count 429 as down?
Down. It is outside the default 200–399 range, so a monitor reports an outage once a second check confirms it. If 429 is the answer you expect from that URL, add it to the monitor’s expected status codes.
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