HTTP is the standard protocol defining how information passes between your visitor’s browser and the server hosting your site and HTTP status codes are your handy way of knowing exactly what is happening within that process.
For web marketers, it’s well worth the effort to get familiar with these status codes. By understanding your site’s backend activity you can recognize errors that demand attention and find opportunities to help improve (or at least not hinder) your SEO[1] efforts.
A quick HTTP status code overview
HTTP status codes are three-digit numbers. The first number indicates which of the five categories each belongs to. The categories refer to either a type of request or type of error, as follows:
1xx status codes: Information request
Status codes beginning with a “1” communicate that a server is processing information, but has not yet completed the request.
2xx status codes: Success
These status codes indicate that a requested information transfer was successfully completed. For marketers seeking to improve SEO[2], these codes mean that no action is required, everything is working correctly.
3xx status codes: Redirection
These redirect codes communicate that your visitor requested information that was not available at the targeted address.
4xx status codes: Client error
These codes signal that the client (the browser accessing the site) has encountered an error[3] when trying to receive server information.
5xx status codes: Server error
5xx codes point to server-side errors, the client request was issue-free and yet the server could not finish the transfer.
Six HTTP status codes that are arguably most critical to SEO
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