HTTP Status codes: What it is & How to check it?

HTTP status codes are responses from a server that reveal how a browser request was handled. These codes help determine if a request was successful if a redirection is needed, or if there’s an issue to address. Understanding these codes is essential for improving website performance and ensuring a smooth user experience. 

This guide explains each status code and provides easy ways to check them, helping you maintain a well-functioning site.

What are HTTP Status Codes?

HTTP status codes are standardized responses from a server to a client (like a browser) following a request. These three-digit codes provide insight into how the server processed the request, with the first digit indicating the response category—whether it was successful, redirected, or encountered an error.

It’s important to note that not all connection issues relate to these HTTP status codes. Errors such as timeouts or connection failures are unrelated to HTTP classes and indicate that the client never connected to the server in the first place. These network or connectivity issues mean the server didn’t receive the request and, therefore, couldn’t respond with an HTTP code. Understanding this distinction helps in diagnosing whether an issue lies with the server response or with connectivity to the server itself.

Why are HTTP Status Codes Important in SEO?

HTTP status codes are essential for SEO because they signal to search engine crawlers whether your content is accessible. A 200 (OK) status code is ideal, showing that pages load successfully and are ready to be indexed. At the same time, a 301 (Permanent Redirect) helps retain SEO value by redirecting link equity to a new URL.

On the other hand, 404 (Not Found) and 5xx (Server Errors) should be avoided. A 404 means a page is missing, which can lead to poor user experience and lost ranking potential. Persistent 5xx errors prevent crawlers from accessing your site, signaling unreliability and potentially causing drops in search visibility. Ensuring your site returns the right codes helps search engines crawl, index, and rank your content efficiently.

The Main Classes of HTTP Status Codes

1xx Informational responses

These codes indicate that the request was received and understood and the server is continuing the process. Users rarely see these codes, which are more informational for ongoing data exchange.

2xx Success

A 2xx code signals that the request was received, understood, and accepted. The most common is 200 (OK), which confirms that the page loaded without issues.

3xx Redirection

These codes mean the requested resource has been moved. For example, a 301 (Permanent Redirect) indicates the content is now at a different URL, helping users and search engines find it.

4xx Client errors

Client errors occur when there’s an issue with the request. A 404 (Not Found) means the requested page doesn’t exist on the server, often due to broken links or mistyped URLs.

5xx Server errors

These codes indicate that the server couldn’t fulfill a valid request. A 500 (Internal Server Error) points to issues on the server side, affecting user access and search engine crawling.

The Most Frequently Used Status Codes in SEO

200 OK

This indicates that the page has loaded successfully and is accessible. This is ideal for SEO, as it confirms that content is available for search engines to crawl and index.

301 Permanent Redirect

Shows that a page has permanently moved to a new URL. This is important for SEO because it passes most of the original page’s link equity to the new URL, preserving ranking power.

302 Temporary Redirect

Indicates a temporary move to a new URL. Unlike a 301, it does not pass SEO value, so it should only be used when the change is not permanent.

304 Not Modified

Tells search engines that the content hasn’t changed since the last crawl, saving crawl budget by preventing unnecessary re-crawling of unchanged pages.

404 Not Found

Indicates that a page is missing. Frequent 404 errors can harm SEO by leading to poor user experience and broken links, so they should be minimized or redirected if possible.

403 Forbidden

This means that the server understood the request but refused to authorize it. Search engines can’t access the content, which may prevent pages from being indexed.

500 Internal Server Error

Signals a general server error, often temporary, that prevents the server from fulfilling the request. Persistent 500 errors can harm user experience and SEO by blocking access to content.

503 Service Unavailable

This indicates that the server is temporarily unable to handle the request, often due to maintenance issues. It can be used with a “Retry-After” header to guide crawlers on when to return.

How to Check HTTP Status Codes?

Google Search Console (URL Inspection Tool):

If you have access to Google Search Console, the URL Inspection tool is a reliable way to check a page’s status code. Simply enter the URL, and it will show whether Google can access the page, its current status, and if there are any issues.

Browser Plug-ins:

You can also add browser plug-ins, like “HTTP Status Code Checker” or “Redirect Path,” to check status codes directly in your browser. These plug-ins provide instant status code information for each page you visit, helping you quickly identify any issues across your site.