URL Mapping

URL mapping is the mapping table that, during a website relaunch, specifies what happens to each old URL: a 301 redirect to the corresponding new page or, if the content no longer exists, a deliberate 404 or 410.

What does this mean for your business?

Without mapping, old links from search results, newsletters, and external websites will lead nowhere after the relaunch. Mapping is a manual process, which is why it should be listed as a separate item in every quote for a website relaunch. Request the mapping table before the site goes live and a verification report afterward. Redirects should be permanent and server-side; according to Google’s own documentation, this gives Google the best chance of interpreting them correctly, and they typically remain in place for at least one year.

Is it enough to redirect all old pages to the homepage?

No. Google explicitly advises against redirecting many old URLs to a single page, such as the homepage, and recommends permanent server-side redirects from each old URL to the corresponding new URL as specified in the mapping. Only if multiple old pages have been consolidated into a single new page should they all point to that page.

From Our Experience

In June 2026, we migrated our own website from WordPress to TYPO3 and to a new domain. The mapping process went as follows:

• We inventoried 437 old URLs from 5 sitemaps and assigned them to 290 target URLs.
• Bulk URLs via pattern rule: 107 out of 116 wiki terms mapped 1:1 using a pattern.
• Each redirect was checked: 437 out of 437 returned a 301 status, and all 290 targets returned a 200 status.

Two issues only came to light during testing. During the first deployment, the robots.txt file returned a 404 error because an allow rule was intercepting WordPress’s virtual robots.txt file. And one glossary term (“Crawlability”) had 128 impressions in Search Console before the move, but 0 at the new URL in the weeks that followed. The redirect worked, but visibility didn’t follow suit immediately; the cause cannot be determined with certainty for a single URL. Google states that temporary fluctuations during a migration are normal. Therefore, the status code test alone is not sufficient. Mapping requires measuring each important URL before and after the migration, using comparison periods of equal length.

Distinction

• A 301 redirect is a single redirect; the mapping is the table from which all 301 redirects are generated.
• Redirect chains occur when the mapping points to a URL that itself redirects instead of responding directly with a 200 status code.
• An SEO relaunch is the entire process, of which mapping is one component.
• The XML sitemap provides a list of the old URLs and, after the migration, a list of the new ones, which you submit to Google.
• Google doesn’t consider the migration fully indexed until Googlebot has visited every old and new URL and processed the redirects.

Red Flag in the Proposal

If the quote simply states “Redirects will be set up”—without an inventory of the old URLs, without a mapping table, and without an audit report—then the mapping is missing. Equally unreliable is the promise that rankings will be completely preserved during the relaunch. Google itself expects fluctuations.

Source

• Google Search Central: Site moves with URL changes, accessed on October 22, 2026
• Google Search Central: Redirects and Google Search, accessed on October 22, 2026