Monday, August 11, 2008
This week we're publishing several blog posts dedicated to helping you with one response code:
404
.
Response codes
are a numeric status (like 200
for "OK", 301
for "Moved Permanently")
that a webserver returns in response to a request for a URL. The 404
response code
should be returned for a file "Not Found".
When a user sends a request for your webpage, your webserver looks for the corresponding file for
the URL. If a file exists, your webserver likely responds with a 200
response code
along with a message (often the content of the page, such as the HTML).
![200 response code flow chart](https://developers-dot-devsite-v2-prod.appspot.com/static/search/blog/images/import/7ca9b8decf36db17266b22c8ec9e8fce.png?authuser=2)
So what's a 404
? Let's say that in the link to "Visit Google Apps" above, the link is
broken because of a typing error when coding the page. Now when a user clicks "Visit Google Apps",
the particular webpage/file isn't located by the webserver. The webserver should return a
404
response code, meaning "Not Found".
![404 response code flow chart](https://developers-dot-devsite-v2-prod.appspot.com/static/search/blog/images/import/dca8c58e19a3260ec0f84bf2cd142403.png?authuser=2)
Now that we're all on board with the basics of 404
errors, stay tuned for even more
information on making 404
errors good for users and for search engines.