Fifteen years of product pages, category pages, guides and blog posts build up a lot of trust with search engines. Every one of those URLs has links pointing at it and a position it has earned. Replatforming almost always changes the URL structure, and if the old addresses simply return an error, that trust is thrown away.
The redirect map, the spreadsheet saying where every old URL should now point, is the least glamorous deliverable of a rebuild. It is also the one that decides whether trade holds up in month two.
Start with a complete list of old URLs
The site's own sitemap is not enough. It misses discontinued products, old campaign pages, and URLs that only exist because someone once linked to them. Build the list from several sources and combine them.
- A full crawl of the current site
- Pages receiving organic traffic in analytics over the last year or more
- Search Console reports of indexed pages and pages with links
- Backlink data from an SEO tool
- Old sitemaps, feeds and marketplace listings
Map by meaning, not by pattern
Some redirects can be generated by rule: every product with a code keeps a page, so the old product URL maps to the new one. Many cannot. Categories get merged or split, discontinued products need a sensible destination, and content gets consolidated. Those decisions need someone who knows the catalogue.
- Send discontinued products to the closest live alternative or their category, not the homepage
- Use permanent redirects, and avoid chains where one redirect leads to another
- Keep redirects in place for years, not months
- Carry across page titles, descriptions and structured data, not just the URL
Redirecting everything to the homepage is the same as redirecting nothing.
Test before launch, and again after
Run the full list of old URLs against the staging site before launch and check that each one lands where it should in a single hop. Then do it again on the live site on launch day. Monitor crawl errors, indexed pages and organic traffic by page type every day for the first few weeks. Problems caught in week one are cheap to fix. Problems found in month three have already cost you the trade.
Expect some movement
Even a well-run migration can see rankings wobble for a few weeks while search engines reprocess the site. The difference is that a careful migration settles back and often improves, while a careless one keeps falling. The redirect map is what separates the two.
