Google Explains How Redirect Settings Affect SEO

Recently, Google representatives provided a detailed explanation of how redirect choices affect ranking signals, canonicalization, and determining which URLs appear in search results. Google’s Gary Illyes and Cherry Prommawin discussed the impact of permanent and temporary redirects. According to them, both types of redirects help the search engine recognize related URLs, but they transmit fundamentally different signals regarding which page should represent the content in search results. 301 vs. 302 Redirects: Key Differences First and foremost, it is important to understand the fundamental difference between 301 and 302 redirects: A 301 redirect tells the search engine crawler that a change in the URL is permanent and that the search index should be updated with the new address. A 302 redirect informs the crawler that a URL change is temporary and that the old URL will eventually be restored. Page Indexing Occurs Regardless of the Redirect Type Used Cherry Prommawin started the discussion by stating that regardless of what redirect is used, a web page is still going to be indexed by Google’s algorithms. However, she emphasized that there are technically correct choices for each scenario: “First of all, relax. No matter which redirect you choose, one of your pages will stay in search and be part of AI training. There are technically correct choices, but getting it wrong is not the end of the world. Google will still index a page. It’s really just a matter of which URL will show up.” She then asked whether Google actually cares if both numbers (301 and 302) successfully take the user to the new page anyway. Gary Illyes replied that for Google's crawlers, it doesn't matter at all, but the real difference lies in the subsequent stages of data processing. The Deduplication Process: How Google Handles Similar Content The conversation then turned to the deduplication process—the stage where Google groups similar pages together and then chooses one page to officially represent all other similar documents in the search index. Gary Illyes noted that the real "battlefield" unfolds during deduplication. Cherry Prommawin detailed this concept: “Ah, the digital family reunion. This is where we look at a room full of identical siblings and try to organize them into a single happy family. So in search deduplication, our system has to group all pages with similar main content together. That’s clustering.” She added that both 301 and 302 redirects will have an effect on clustering similar pages together. However, only the 301 redirect will have a canonicalization effect. Illyes continued: “…then our index has to select just one official URL to represent this entire flock in the search results. Basically, within a cluster, we choose one representative page. The final selection process is called canonicalization.” UAMASTER's Expert View on Content "Cannibalization" At the UAMASTER agency, we frequently encounter client inquiries regarding so-called "content cannibalization." This concept, popular among SEO professionals since the early 2000s, claims that if a group of pages is too similar, Google chooses not to rank any of them because the ranking signals are allegedly diluted. However, the latest statements from Google representatives completely confirm our expert position: the concept of "cannibalization" in its classical sense is a myth. The system clusters similar pages, selects one as the canonical URL, and accumulates all ranking signals onto that single address. What many marketers call "cannibalization" is actually the result of other fundamental issues: a lack of unique value, thin content, or problems with site architecture. A 301 Redirect Transfers Ranking Signals Another critical aspect we at UAMASTER always highlight during technical audits: A permanent redirect (301) transfers ranking signals from the old URL to the new one. Google does not transfer ranking signals when it encounters a temporary redirect (302). Gary Illyes explained the mechanics: “Google takes all the ranking signals of the old page and hands them to the new page.” Regarding the 302 redirect, the search engine's logic is different: “Google assumes you are going back eventually, keeps the old URL in the search results, and basically ignores the new URL.” Therefore, using a 302 redirect for permanent changes will result in a loss of SEO potential for the new page. Recommendations for Using 307 and 308 Redirects The experts also discussed 307 and 308 redirects. Generally, they serve the same basic temporary and permanent functions as the 302 and 301. The main technical difference lies in how browsers handle submitted "POST" data (e.g., filling out registration forms or entering payment details). A 308 redirect is the more modern version of a permanent 301 redirect. A 307 redirect is the modern version of a temporary 302 redirect. Imagine a scenario: during a massive Black Friday sale, a user fills out a checkout form with their credit card details and hits "Submit." If the primary server is overloaded, a quick redirect to a backup server is triggered. If the site uses a classic 302 redirect, the data is lost, and the client sees an error. Instead, a 307 redirect instructs the browser to keep the data intact and forward it to the new server. The transaction goes through successfully. For e-commerce projects, we at UAMASTER highly recommend taking this feature into account when designing the architecture of high-load systems. Google Recommends Server-Side Redirects Over JavaScript and Meta Refreshes Finally, the company's representatives emphasized that Google recommends using exclusively server-side redirects. We fully support this point: outdated redirection methods using meta tags (meta refresh) or JavaScript should be abandoned. Gary Illyes explains it simply: “A server-side HTTP redirect is a clean, instant instruction. JavaScript and meta refreshes force the browser to download the page, parse the code, wait for the script to execute, and then launch the user somewhere else.” This degrades page loading speed and negatively impacts Core Web Vitals metrics. Summary and Recommendations from the UAMASTER Team Redirects are not just a technical developer's tool. They are a powerful communication channel with the search engine that directly impacts your business's SEO results. Key takeaways for marketers: Use a 301 redirect for all permanent URL changes on your site. Only this type can transfer the authority (ranking signals) accumulated over the years to the new page and correctly indicate the canonical URL. Do not fear "content cannibalization" just because you have similar pages. Instead, focus on creating unique user value on each page; the search engine will handle the technical part (canonicalization) on its own (or with the help of properly configured rel="canonical" tags and 301 redirects). For complex forms and e-commerce payment systems, it is advisable to consider using 307 and 308 redirects to prevent user data loss during redirections. Still have questions about the technical SEO of your project? The UAMASTER team is always ready to help with audits and the implementation of cutting-edge solutions to grow your business in search. Read this article in Ukrainian.