If you are new to SEO, you often hear codes being thrown about like 301, 404 and 302. There are four HTTP status codes 200, 301, 302, 404 that you should be primarily interested in from an indexing and search engine marketing perspective.
The entire list of error codes can be be found on the W3C website.
CODE: 200: — DEFINITION: Status OK
The file request was successful. For example, a page or image was found and loaded properly in a browser.
When a search engine crawls a URL and receives the result code 200 then it thinks the content is valid and will try to add it to the index. When it gets a 404 it know that the URL is no longer valid and will remove it
CODE: 301 – DEFINITION: Moved Permanently
The file has been moved permanently to a new location.
This is the preferred method of redirecting for most pages or websites. If you are going to move an entire site to a new location you may want to test moving a file or folder first, and then if that ranks well you may want to proceed with moving the entire site. Depending on your site authority and crawl frequency it may take anywhere from a few days to a month or so for the 301 redirect to be picked up.
- W3C HTTP 1.1 Status Code Definitions
- On Apache servers you can redirect URLs in a .htaccess file or via in the headers of some dynamic pages. Most web hosts run on Apache.
CODE: 302 – DEFINITION: Found
The file has been found, but is temporarily located at another URI.
As a good rule of tumb in regards to SEO, it is typically best to avoid using 302 redirects. Some search engines struggle with redirect handling. Due to poor processing of 302 redirects some search engines have allowed competing businesses to hijack the listings of competitors.
CODE: 404 – DEFINITION: Not Found
The server was unable to locate the URL.
Some content management systems send 404 status codes when documents do exist. Ensure files that exist do give a 200 status code and requests for files that do not exist give a 404 status code. You may also want to check with your host to see if you can set up a custom 404 error page which makes it easy for site visitors to
- View your most popular and / or most relevant navigational options
- Report navigational problems within your site
- Search your site
- View your sitemap
Search engines request a robots.txt file to see what portions of your site they are allowed to crawl. Many browsers request a favicon.ico file when loading your site. While neither of these files are necessary, creating them will help keep your log files clean so you can focus on whatever other errors your site might have.