How do you avoid losing SEO traffic during a website redesign or migration?
A redirect map and a pre-launch crawl are what save the traffic, not hope.
Crawl and baseline the old site before anything changes, build a one to one 301 redirect map for every URL that will move, and verify the redirects the hour you launch. Traffic losses in a redesign are almost always a missing redirect, not an algorithm.
Before launch
- Crawl the old site and export every live URL. This list is the source of truth for the redirect map.
- Baseline the numbers. Search Console queries, impressions and clicks per page, GA4 landing page sessions, and current rankings for your money terms. If you do not record this, you cannot tell later whether you lost anything.
- Identify your top pages by traffic and by revenue, and keep their content, titles and headings substantially intact. Redesign the shell, not the words that are already ranking.
- Build the redirect map. Every old URL to its closest new equivalent. One hop, no chains. Do not dump everything to the homepage: that is treated as a soft 404 and you lose the equity.
- Check the staging site is blocked from indexing, and check that the block is removed at launch. Both halves of that get forgotten.
Launch day
Re-crawl immediately and test the redirect list mechanically, not by clicking a few. Confirm the new site is not carrying a sitewide noindex tag. Submit the new sitemap. Verify analytics and conversion tracking fire on the new templates, because a redesign is the most common way tracking silently breaks.
After launch
Expect a dip. A short, shallow wobble for two to four weeks while Google recrawls is normal. What is not normal: an immediate cliff, a spike in coverage errors, or specific high value pages dropping out entirely. Those are broken redirects and they are fixable if you catch them in week one. Watch Search Console coverage and broken links weekly for a month.
We run this checklist on every redesign and every platform move, including migrations onto a new build.
Related: Can you redesign our existing website instead of starting from scratch?, What is technical SEO and what does it cover?, How long does a website build take?