Wirebook › Glossary › Status code
What is a status code?
In one sentence: The three-digit number at the start of every response, such as 200 or 404.
A little more
Every web response starts with a three-digit number. The first digit tells you the family: 2xx worked, 3xx look somewhere else, 4xx the request was wrong (404 Not Found, 429 Too Many Requests), 5xx the server had a problem (500, 503).
You usually only notice them when something goes wrong, but your browser reads one for every single request.
It's a bit like… The little icon on a parcel tracker: delivered, redirected, wrong address or depot problem.
See it in action
- 5What do 404 and friends mean?The three-digit codes behind every web page, explained: 200, 301, 404, 429, 500 and the 418 teapot.5 min · interactive
- BonusWhy can a download pick up where it left off?Break a pretend file into numbered pieces, interrupt the download, and compare restart-from-zero with resume-using-byte-ranges.6 min · interactive