Server Response Code Chart

Also known as HTTP Status Codes

Although this is a complete (as of 10/20/2005) list of response codes we have tried to make application to how these codes can be affecting your site ranking and position in search engines.
If you don't know what status codes your site is serving use our tool for viewing these: HTTP header viewer

If you don't know how to set response codes check this page Set Status Codes

Codes from 100 - 199

100 Continue
101 Switching Protocols

Codes from 200 - 299 Successful

200 OK

This is the only status code that you really want to see. This means that everything worked perfectly, you've got a smashing site, congratulations.

201 Created
202 Accepted
203 Non-Authoritative Information
204 No Content
205 Reset Content
206 Partial Content

Codes from 300 - 399 Redirection

300 Multiple Choices
301 Moved Permanently

This is the correct status to serve if you have moved a page. Most search engines will respect this type of page move. The redirection will be followed and the new page indexed.
All of the other redirection status codes can cause trouble from an SEO standpoint, so avoid them at all costs.

302 Found Moved Temporarily
303 See Other
304 Not Modified
305 Use Proxy
307 Temporary Redirect

Codes from 400 - 499 Client Error

None of the response codes in the 400 range are good. The good news is that most of the time the fault is the users. Many times they have entered an incorrect URL, or tried to access a page that they do not have authorization for.

400 Bad Request
401 Unauthorized
402 Payment Required
403 Forbidden
404 Not Found

This is the one we need to be careful of. If you have broken links within your site that will cause trouble. Links comming in from search engines and other sites also need to work. If you move a page or a section of your site be sure to redirect and set an appropriate status code so these pages are not lost from your sites structure on search engines. Any webmaster that is paying attention will remove broken links from his site to yours immediately, if he's a philanthropist he may send you an email before removing it, but of course it will take weeks to get that hard earned link back in place. Don't let that happen.

405 Method Not Allowed
406 Not Acceptable
407 Proxy Authentication Required
408 Request Timeout
409 Conflict
410 Gone The URI no longer exists and has been permanently removed from the server.
411 Length Required
412 Precondition Failed
413 Request Entity Too Large
414 Request-URI Too Long
415 Unsupported Media Type
416 Requested Range Not Satisfiable
417 Expectation Failed

Codes from 500 - 599 Server Error

These ones are all you. Contact the tech department, hire a programmer, or brush up on your skills. The 500 range of server response codes are all server based errors. Most often these errors are caused by mistakes in programming, or a server down.

500 Internal Server Error
501 Not Implemented
502 Bad Gateway
503 Service Unavailable
504 Gateway Timeout
505 HTTP Version Not Supported