HTTP status codes explained
Every response from a web server starts with a three-digit number, telling the browser and search engine what's going on with the requested address, and the first digit indicates the direction.
| Area | Significance |
|---|---|
| 2xx | Has worked out |
| 3xx | To be found elsewhere |
| 4xx | Error in the request |
| 5xx | Error in the server |
The ones you really meet
- 200 OK – All right, the page comes along. Only such addresses belong in a sitemap.
- 301 Moved Permanently – Permanently moved. Search engines take over the address and its effect.
- 302 Found – Temporarily somewhere else. The old address remains the authoritative one.
- 304 Not Modified – Unchanged – the browser takes its saved version. Saves loading time.
- 401 Unauthorized – Registration is required.
- 403 Forbidden – Access denied. Often a rights issue on the server.
- 404 Not Found – Normal and harmless – problematic only if internal links point to it.
- 410 Gone – The page existed but has been deliberately removed. Clearer than a 404; Google removes the page from its index faster.
- 429 Too Many Requests – Too many requests. The server throttles.
- 500 Internal Server Error – Something is broken. Apache often has a typo in the .htaccess.
- 503 Service Unavailable – Temporarily unavailable – the correct code for maintenance work.
During maintenance work
Take 503 with one or more Retry-After-Header, not 404 and not a 200 page with "We're right back" only 503 tells the search engine: Come back later, the content isn't gone.
Suitable tools
Further in Technology
- 301 or 302? – The decision takes five seconds – and the wrong one costs visibility.
- What is DNS? – The address book of the Internet – and why changes do not take effect immediately.
- Switch your website to HTTPS – In five steps – and with the two places where it almost always sticks.