Renaming a page, restructuring a site, or moving to a new domain name almost always requires changing certain addresses. Without proper redirection, every modified URL becomes a page visitors cannot find if they had bookmarked the old address, as well as for Google, which has to start from scratch to understand the content now exists elsewhere. The 301 redirect remains the standard tool for avoiding this loss, but its effectiveness depends entirely on how rigorously it is set up.
What a 301 redirect actually does
The 301 status code means permanently moved. When a browser or crawler requests the old address, the server responds with this code and the new destination, to which the request is automatically forwarded. Google treats this signal as a clear indication that the content has permanently moved, and transfers nearly all the ranking value accumulated by the old page to the new one, including the inbound links that pointed to it. Contrary to a belief dating back to the early days of search engine optimization, no automatic penalty applies to a correctly configured 301 redirect.
The redirect chain trap
A redirect chain occurs when one address redirects to a second, which itself redirects to a third, rather than pointing directly to the final destination. Each additional link slows down the page's loading for the visitor and makes the crawler's job harder, since it may give up following an overly long chain. This problem often builds up gradually, as a site accumulates several migrations, structural changes, or plugin updates over the years, with no one cleaning out old redirects that have become unnecessary. The rule to follow remains simple: every old address must point directly to its final destination, never to an intermediate step.
The redirect loop trap
A loop occurs when an address ends up redirecting to itself, directly or after several steps, entirely preventing the page from loading for both visitors and crawlers. This case, rarer but more severe than a simple chain, often happens after a poorly tested change to a configuration file or a redirect management plugin, and must be fixed urgently as soon as it is detected.
301 or 302: a distinction that changes everything
The 302 code indicates a temporary move, and Google then keeps the old page in its index, deferring the transfer of ranking value rather than carrying it out immediately as with a 301. Using a 302 for a change that is actually permanent, a common mistake since many tools apply this code by default, therefore prevents the expected ranking transfer. The 302 keeps its usefulness for genuinely temporary cases, such as a maintenance page or a one off test, but should be replaced with a 301 as soon as the change becomes definitive.
Building a mapping before migrating
Before any large scale migration, the recommended practice is to draw up a complete list of old addresses and individually pair each one with the most relevant new address, rather than redirecting the entire site to the homepage for apparent simplicity. This blanket approach, sometimes chosen to save time, dilutes the relevance of each redirect in Google's eyes and can be treated as a soft error rather than a successful redirect, with a negative effect on the ranking of every affected page.
Checking after going live
Tools such as Screaming Frog let you crawl an entire site and automatically spot chains, loops, and redirects using the wrong code. A more targeted check on a specific address can be done directly through the command line, or via a browser extension that shows the full path a request follows. This check is worth repeating regularly after the initial migration, since plugin updates or later changes to the site can reintroduce new chains without anyone noticing immediately.
Points to verify before publishing: confirm that the description of how Google treats 301 versus 302 redirects differently remains accurate at the time of publication, and check that the tools mentioned for auditing redirects (Screaming Frog, browser extensions) remain commonly used market references.