Hyvä migration: what to expect in week one
A Hyvä migration is mostly a frontend swap. Magento Open Source or Adobe Commerce stays where it is. Catalog, orders, customers, payment integrations are untouched. What changes is the theme layer.
Most teams take 2 to 4 weeks. The actual code work is a fraction of that. The rest is decisions: which third-party modules need a Hyvä compatibility module, what to do with custom Luma overrides, and how to handle the inevitable storefront-specific edge cases your team built years ago and never documented.
The week-one shape
The first week sets the velocity for everything that follows. Done well, you have a Hyvä theme rendering against your staging database with most of the catalog intact and your top three checkout flows passing manual tests. Done badly, you find yourself debugging Luma JS leftovers in week three.
What actually happens in week one:
Day 1: Audit and inventory. Every third-party module in your Composer file gets checked for Hyvä compatibility. Some have official compatibility modules. Some have community ones. A few have nothing, and you decide whether to build, patch, or remove.
Day 2-3: Install Hyvä, run the default theme. Get the green Hyvä storefront running against your real product data. Confirm cart, checkout, and account flows work with the out-of-the-box theme.
Day 4-5: Brand the default. Colors, typography, logo, header, footer. Hyvä's Tailwind setup makes this faster than the equivalent Luma work by a significant margin.
What we wish we had known before week one
A few things that don't make most Hyvä migration guides but cost real time:
- PWA Studio leftovers. If the store ever had PWA Studio installed, expect ghost service-worker references and stale manifests. Audit
pub/staticearly. - Custom Knockout components. Anything in
view/frontend/web/jsthat uses Knockout needs a rewrite to Alpine or a Hyvä-native equivalent. Plan for this. It's the part that surprises teams. - Email templates. Order and customer email templates still use the legacy Magento renderer. Don't assume they'll need rework. Test them before launch.
- Third-party module configs. Some compatibility modules need additional admin config that's easy to miss. Hyvä Themes maintains a list. Check it.
The metric that matters
Lighthouse Performance is the test we run before sign-off. The Hyvä default theme on a properly configured Magento store sits in the 80-95 range out of the box. If your migration drops below 70, something is wrong, usually a third-party module bleeding Luma assets into the Hyvä build.
We have seen migrations land at 92 mobile in three weeks. We have also seen ones drag for three months because the team kept adding modules without measuring impact. The discipline is the same as any other performance work: budget, measure, ship.
Who Hyvä is not for
Hyvä is opinionated about how the frontend should work. Tailwind, Alpine, server-rendered HTML. If your team is committed to a heavily-customized React or Vue storefront, Hyvä is not the path. You want a headless setup with Adobe Commerce or a separate PWA stack.
For most Magento stores, though, Hyvä is the cheapest large performance win on the table. Smaller bundles, faster paint, less JS to debug. Worth the migration cost in nearly every case we have seen since 2021.