3xx status codes are the group of HTTP status codes that indicate redirection or reuse-related responses. When a user tries to access a web page through a browser, the browser sends a request to the relevant server. The server responds to this request with a three-digit HTTP status code. If the request is processed successfully, 2xx codes are usually returned. If redirection is needed, 3xx codes appear. If there is a client-side issue, 4xx codes are returned. If there is a server-side error, 5xx codes are shown.
3xx status codes indicate that an additional action is needed to complete the request. In most cases, this action means that the user or browser should be redirected to a different URL. For this reason, 3xx codes are also known as redirect status codes. However, not every 3xx code sends the user to a new address in the classic sense. For example, 304 Not Modified is related to browser caching and indicates that the resource does not need to be downloaded again.
These codes are important for SEO because they help search engines reach the correct page during URL changes, site migrations, category updates, product removals and domain changes. Correctly used 3xx redirects protect user experience, transfer traffic from old URLs to new pages and can help search engines understand the site structure more accurately. Incorrect redirects, however, can cause crawling issues, ranking loss, redirect chains or user experience problems.
One of the most common 3xx codes is 301 Moved Permanently. A 301 indicates that the requested resource has permanently moved to another URL. When a page URL changes permanently, the old page should be redirected to its new equivalent with a 301. For example, when a category URL is changed, users and search engines visiting the old address are redirected to the new category page. A 301 is commonly used for domain changes, site migrations, HTTP to HTTPS transitions or merging two pages.
A 301 redirect should be treated as a permanent decision. If a page will be redirected to another address only for a short period, using a 301 may not be appropriate. This is because a 301 tells browsers and search engines that the old URL has been permanently replaced by the new URL. Therefore, temporary campaign, maintenance or testing scenarios may be better handled with temporary redirects such as 302 or 307.
302 Found indicates that the resource is temporarily available through another URL. In this case, the user is redirected to another page, but the original URL is not considered permanently changed. A 302 can be used for temporary campaign pages, short-term location redirects or maintenance-related temporary redirects. From an SEO perspective, a 302 signals to search engines that the old URL may still be considered the main address.
307 Temporary Redirect also means temporary redirection, but it defines a more specific behaviour than 302. With a 307 redirect, the browser should continue the request to the new address without changing the HTTP method. In other words, a POST request remains POST and a GET request remains GET. Because some clients historically converted POST requests into GET requests with 302 redirects, 307 provides clearer temporary redirect behaviour. This difference is especially important for form submissions, API requests and transaction flows.
308 Permanent Redirect is similar to 301 because it indicates a permanent redirect, but like 307, it requires the HTTP method to be preserved. This means the resource has permanently moved and the browser should forward the request to the new address using the same method. A 308 can be useful in modern web applications and API structures where more controlled permanent redirect behaviour is needed. For classic web page migrations, 301 is still the most commonly used permanent redirect code.
303 See Other tells the client to retrieve the response from a different URL, usually with a GET request. It can be used especially after form submissions to redirect the user to a result or thank-you page. For example, after a user submits a form, a 303 can help prevent duplicate form submissions and take the user to a result page. This code is more common in application flows than in classic SEO redirects.
304 Not Modified belongs to the 3xx class but does not redirect the user to another URL. It tells the browser that the previously downloaded resource has not changed and that the cached version can be used. This can improve page load performance and reduce unnecessary data transfer. A 304 is not related to URL migration; it is an HTTP response associated with cache control.
In SEO work, 3xx codes should be planned correctly. If a page has permanently moved, 301 should be used. If it has moved temporarily, 302 or 307 should be used. There should be a strong relationship between the old URL and the new URL in terms of topic and user intent. For example, redirecting an old “sports shoes” category page to an unrelated homepage is not a good practice. When users arrive through the old URL, they should reach the closest relevant new page.
Redirect chains and loops should also be monitored carefully. A redirect chain occurs when one URL redirects to a second URL, which redirects to a third URL, and then to another URL. This can negatively affect page speed, crawl efficiency and user experience. A redirect loop occurs when URLs keep redirecting to one another and the final page cannot be reached. These issues create serious problems for both users and search engines.
3xx redirects play a critical role in site migrations. Old URLs should be mapped to their new equivalents in advance, a redirect map should be prepared, important pages should be checked individually and redirects should be tested to ensure they work correctly. Sitemap files should also be updated with the new URLs, and internal links should point directly to the new addresses rather than the old ones. This reduces unnecessary redirect load and provides a cleaner site structure for search engines.
3xx codes are important not only for SEO but also for user experience. When users click an old link, bookmark, campaign link or search result, they expect to reach the correct page. If the redirect works properly, they can access the content without interruption. However, incorrect redirects, mass redirects to the homepage, irrelevant destination pages or infinite redirect loops can damage user trust.
Analytics and measurement should also be considered in redirect management. Campaign URLs, UTM parameters, cross-domain transitions and checkout steps can all be affected by redirects. Misconfigured redirects can break source/medium data, split sessions or cause conversion tracking to work incorrectly. Therefore, 3xx redirects should be evaluated not only by technical teams, but also together with SEO and analytics teams.
3xx status codes can be detected using crawl tools, server logs, Google Search Console, browser developer tools, CDN reports and technical SEO tools. Redirect checks should always be performed after site migrations, URL revisions, CMS changes or HTTPS transitions. Which URL returns which status code, how many steps it takes to reach the final page and whether the destination page is correct should be monitored regularly.
In summary, 3xx status codes are HTTP response codes indicating that an additional action is needed after a request, usually because the resource is being redirected to another address. A 301 is a permanent redirect, 302 is a temporary redirect, 307 is a temporary redirect that preserves the HTTP method, 308 is a permanent redirect that preserves the HTTP method, and 304 is related to cache reuse. When used correctly, 3xx codes protect user experience, support healthy site migrations and help prevent SEO performance loss.
