Most migration failures are sequencing failures. The list below is ordered deliberately — doing step six before step two is how stores lose a third of their organic traffic.
Before anything is built
1. Export every URL. From your CMS, your sitemap, Search Console and your analytics. The four lists will not match, and the union of them is your real URL inventory.
2. Rank them by traffic and links. You cannot map everything manually. Sort by sessions and by referring domains; the top of that list is what must not break.
3. Export the product data and read it. Not just the count. Look at how variants, options and custom fields are actually structured, because that mapping is the bulk of the work and it is where quotes go wrong.
4. Inventory the apps and integrations. Each one is a workstream. An integration discovered in week five costs five times what it costs in week one.
If an agency has quoted without seeing a real catalogue export and a URL list, the number is a guess. This is the single most reliable tell in migration quoting.
While building
5. Build the redirect map as a document, not as code. Old URL to new URL, reviewed by someone who knows the business. Redirecting everything to the homepage is worse than a 404 — Google treats it as a soft 404 and you lose the signal either way.
6. Reproduce structured data. Product, breadcrumb, and anything else the old site emitted.
7. Keep the titles and headings. A rebuild is the wrong time to also rewrite every title tag. Change one variable at a time.
Before cutover
8. Test the redirects on staging. Every mapped URL, automatically, with the result recorded. This is a script, not a spot check.
9. Check the new site is crawlable. The most common launch failure in this whole list is a staging noindex shipped to production.
10. Have a rollback you could actually execute. Not theoretical.
At cutover
11. Go live, then submit the new sitemap immediately.
12. Watch Search Console daily for two weeks. Coverage errors, 404 spikes, and the index count.
The mistake worth naming
Do not redesign at the same time. When traffic moves you will not know whether the platform, the URLs or the new design caused it. Migrate, stabilise, then redesign.
It is slower and it is the difference between a diagnosable outcome and a mystery.
Talk it through
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About the author
Manpreet Singh
Founder of Proscube. Leads the studio's Shopify, headless and CRO engineering, and works directly with founders rather than through account managers.
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