Redirect mapping for a site migration
A site migration — new platform, new domain, or a redesign with new URLs — is where most SEO traffic is won or lost. A redirect map pairs every old URL with its new equivalent so visitors and rankings carry over. Here's how to build one properly.
How to build a redirect map for your migration
- 1
Export your old URLs
Collect every URL on the current site from multiple sources so you don't miss any: crawl the live site (Screaming Frog, Sitebulb), export your XML sitemap, pull top pages from Google Analytics and Search Console, and check backlinks (Ahrefs/Semrush) for externally-linked URLs.
- 2
List your new URLs
Export the new site's URL structure — its sitemap or a crawl of the staging site. This is the set of live destinations each old URL can map to.
- 3
Match old URLs to new URLs
Pair each old URL with its closest new equivalent. For a handful, do it by hand; for hundreds or thousands, use a redirect map generator that scores each old URL against your new URLs by path structure and keywords and suggests the best match.
- 4
Use 301 (permanent) redirects
Every migration mapping should be a 301 so search engines transfer ranking equity from the old URL to the new one. Redirect each URL to the most relevant page — never blanket-redirect everything to the homepage (Google treats that as a soft 404).
- 5
Implement the redirects at launch
Add the redirects in your server config (.htaccess / nginx), CDN, or CMS/redirect app so they're live the moment the new URLs go public. Test a sample in an incognito window before and immediately after launch.
- 6
Monitor for missed URLs after launch
No redirect map is complete. After launch, watch Google Search Console for new 404s and use real-time 404 monitoring to catch broken URLs — stale external links, typos, forgotten pages — and redirect them as they surface.
Automate 404 recovery with Redirect Mapper
Redirect Mapper covers both halves of a migration: the free redirect map generator builds your pre-launch old→new map in seconds, and the automated snippet catches every 404 that slips through after launch — matching it to the closest live page in real time and logging it for a clean 301 export.
Frequently asked questions
Redirects should be live the moment the new URLs are public — ideally deployed with the launch, not after. Any gap where old URLs 404 loses traffic and can drop rankings, so test the redirect rules on staging and flip them on at cutover.