4xx Client error
HTTP 428 Precondition Required
The server requires the request to be conditional, for example with an If-Match header. It prevents lost updates: a client that changes a resource must show it has the latest version.
Defined in RFC 6585, section 3(opens in a new tab)
//_01 Uptime checks
Is 428 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 428 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 428 comes from a server that is running.
//_02 Causes and fixes
Why you see 428 and what to do
Typical causes
- An API that refuses changes without an ETag condition.
If you run the site
- Explain in the response which header to send.
If you’re a visitor
- Nothing to do in a browser.
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 428 mean?
The server requires the request to be conditional, for example with an If-Match header. It prevents lost updates: a client that changes a resource must show it has the latest version.
Does an uptime monitor count 428 as down?
Down. It is outside the default 200–399 range, so a monitor reports an outage once a second check confirms it. If 428 is the answer you expect from that URL, add it to the monitor’s expected status codes.
Downtime is obsolete.
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