3xx Redirection
HTTP 303 See Other
The server sends the client to another URL to be fetched with GET, typically after a form was posted. Reloading the result page then doesn’t send the form again (the Post/Redirect/Get pattern).
Defined in RFC 9110, section 15.4.4(opens in a new tab)
//_01 Uptime checks
Is 303 up or down for a monitor?
Uptimecheck HTTP monitor
Default settings
Up, as long as the page it leads to is. A monitor follows redirects by default, up to 10, and judges the final answer. With Follow redirects turned off, the 303 itself is judged, and it is within the default 200–399 range.
Is it down? checker
Free, at /is-it-down/
It follows up to 5 redirects and judges the final answer: anything below 500 counts as the site answering.
//_02 Causes and fixes
Why you see 303 and what to do
Typical causes
- A form or checkout that redirects to a confirmation page after it is submitted.
If you run the site
- Use it after POST requests that change something, so a reload or the back button can’t submit twice.
If you’re a visitor
- Nothing to do.
Know the moment your site stops answering as it should
An Uptimecheck monitor requests your page as often as every minute, checks the status code against the ones you expect, confirms a failure with a second check and then alerts you.
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Questions
What does HTTP 303 mean?
The server sends the client to another URL to be fetched with GET, typically after a form was posted. Reloading the result page then doesn’t send the form again (the Post/Redirect/Get pattern).
Does an uptime monitor count 303 as down?
Up, as long as the page it leads to is. A monitor follows redirects by default, up to 10, and judges the final answer. With Follow redirects turned off, the 303 itself is judged, and it is within the default 200–399 range.
Downtime is obsolete.
Set up your first monitor in under a minute, or look around the live demo first.
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