When undertaking technical SEO audits or diagnosing technical issues with a website it is important for an SEO to understand what the most common HTTP status codes are and when they should be used. This article will explain what they are, when and why they occur, and most importantly how to utilise them effectively.
What are HTTP status codes? What are the most common status codes? How to check and test status codes? What are the different classes of status codes?
What are HTTP Status Codes?
Each time you visit a new page on a website (or a page anywhere across the web), your browser sends a request to that website’s server. The response to the request is a three digit code from the server - this is the HTTP status code. This code acknowledges the request from the client and represents the response from the server. There are hundreds of different codes, with each code serving a different purpose. These codes let you know if a page is functioning correctly or if there are issues, and if there are, what issue is occurring. When bots crawl a website it will request web pages in the same way a browser does - the HTTP code directs this exchange. SEO specialists can implement certain codes across a site to create different journeys for users and bots. That is, to change the path of a user or a bot when crawling a site. Status codes can be used to pass or block link equity flowing through pages also. As these codes are handled differently by search engines, it is important to use them correctly! If a code is used incorrectly your site could face major technical SEO issues. This is why search engine optimisation (SEO) specialists need to understand the HTTP protocol and how these affect bots crawling and indexing pages. SEO specialists also need to understand common status codes, to inform technical SEO strategies and to diagnose issues on a website. Below, we will break down common HTTP codes, when to use these codes and how these codes should be implemented for best practice SEO.
What are the most common status codes?
200 (OK) 301 (Moved Permanently) 302 (Moved Temporarily) 307 (Temporary Redirect) 404 (Not Found) 410 (Gone) 500 (Internal Server Error) 503 (Service Error)
How do you check and test status codes?
There are different tools that can be used to check the HTTP status code of a URL, with some being more efficient than others.
Using built-in browser tools to check the HTTP status code
To access Chrome’s built in tools, Open Chrome DevTools and access the ‘Network’ tab to see network activity. Users often find this tool a little clunky and prefer to use a browser plug-in tool when testing URLs (see below).

Using a browser plug-in (Redirect Path) to check the HTTP status code
Redirect Path is a popular browser plug-in by Ayima. This tool allows the full exploration of a HTTP response. The Chrome plug-in can be downloaded here.

An example of the response codes for Ayima’s website - there is a 301 redirect to the HTTPS version of their site.

This is the full HTTP response for our URL using Redirect Path
Using Google Search Console to check the HTTP status code
The URL Inspection feature within Google Search Console allows you to request HTTP responses. Once you request a URL, open up the ‘Coverage Panel’. Within this, the “Page fetch” defines the HTTP response. When we request the URL: https://www.semetrical.com/technical-seo/, the tool returns a response of ‘Successful’ which represents the 200 Ok status code.
