HTTP status codes: 200, 301, 404, 500 and the rest

Updated 23 September 2026

For every page requested, the server answers with a three-digit code. That code tells the browser, and Google, whether all is well, whether the page has moved or whether something failed. Knowing how to read it saves a lot of time.

The five families

Family	General meaning
1xx	Information: the request is being processed
2xx	Success: the request went through
3xx	Redirection: the resource is elsewhere
4xx	Client error: the request is wrong or not allowed
5xx	Server error: the request was valid, but the server failed

The codes to know

Code	Name	What it means
200	OK	The page is served normally
204	No Content	Success, with nothing to send back
301	Moved Permanently	The page has moved for good
302	Found	Temporary redirect
304	Not Modified	The browser can use its cached copy
307 / 308	Temporary / permanent redirects	Like 302 and 301, but the method (POST…) is kept
400	Bad Request	Malformed request
401	Unauthorized	Authentication required
403	Forbidden	Access denied, even when authenticated
404	Not Found	The page does not exist
410	Gone	The page was removed for good
429	Too Many Requests	Too many requests, rate limit reached
500	Internal Server Error	Error in the server's code or configuration
502	Bad Gateway	An intermediary got no valid answer from the origin server
503	Service Unavailable	Server overloaded or under maintenance
504	Gateway Timeout	The origin server took too long to answer

What Google does with them

301 and 308 pass the value of the old page to the new one: use them for any permanent move, URL change or switch to HTTPS.
302 and 307 signal a temporary change: Google usually keeps the old URL in its index.
404 and 410 remove the page from the index over successive crawls; 410 is slightly faster. A few 404s are normal and do not penalise the site.
Repeated 5xx errors slow down crawling: Google comes back less often to a site that keeps failing.
**503 with a Retry-After header** is the right response for maintenance: Google understands it is temporary.

A classic trap: the "soft 404", an error page returned with code 200. Google detects it and flags it in Search Console; return a real 404.

Diagnosing an error

404: check the spelling of the URL and the links pointing to it. If the page moved, set up a 301 redirect to the new address.
403: file permissions on the server, a firewall rule, or IP-based protection.
500: read the server's error log; it is often a code or configuration error introduced by the latest update.
502 / 504: the origin server is down or too slow behind a proxy or CDN. Check that it answers directly.
Redirect chains: A to B to C slows the page and dilutes the signal. Point A straight to C.

Our HTTP headers tool shows the code returned by a URL, the redirects followed and the response headers: the quickest way to see what Google and browsers see.

Open the NetCheck tools

Frequently asked questions

What is the difference between 301 and 302?

301 is permanent: Google replaces the old URL with the new one in its results. 302 is temporary: the old URL stays indexed. For a lasting move, use 301 or 308.

Do 404 errors hurt SEO?

Not in themselves: a deleted page should return 404. The problem is internal links pointing to pages that do not exist, and important pages removed without a redirect.

Why does my site return 403 to some tools but not to the browser?

Some firewalls block requests that do not look like a browser, or certain IP ranges. Check the security rules of your host or CDN.