Going headless is usually the right call for a brand that has outgrown its theme. Faster pages, full control, a checkout that fits the business. But a replatform is also the single most effective way to tank an established storefront's search rankings, and most of the damage is self-inflicted and avoidable.
Here's the short version of how I protect rankings through a migration.
Map every URL before you touch anything
Export the full list of indexed URLs — products, collections, content, the long tail of legacy pages that still rank. For each one, decide: does it survive, redirect, or die? A 301 to the closest live equivalent preserves most of the link equity; a 404 throws it away.
The pages you forget are the ones that were quietly ranking. Pull the URL list from Search Console, not just your sitemap.
Match metadata one-to-one
Title tags, meta descriptions, canonical tags, and structured data should come across unchanged unless you have a specific reason to improve them. A redesign is not the time to also rewrite every title — change one variable at a time so you can tell what moved the needle.
<link rel="canonical" href="https://example.com/products/the-thing" />
<meta property="og:title" content="The Thing — Brand" />Server-render the pages that rank
This is where headless earns its reputation, good or bad. If your product and collection pages render client-side, crawlers see an empty shell and your rankings follow. Render them on the server so the full HTML — copy, metadata, structured data — is in the initial response.
Launch behind a staged rollout
Don't flip the whole site at once. Roll out by template — collections first, say — and watch Core Web Vitals and rankings daily. Keep the old stack warm so you can roll back a template without rolling back the whole project.
Launch into a low-traffic window, not the week before your biggest sale.
What good looks like
A migration done this way is boring, and boring is the goal: faster pages, a checkout you control, and a rankings chart that doesn't notice anything happened. If your traffic dips and recovers in a few weeks, that's a tax you didn't need to pay.
If you're planning a replatform and the SEO risk is keeping you up at night, that's a conversation worth having before the build starts, not after.