Will the Hyvä migration affect my SEO rankings?

Yes — positively, if done right. URLs, redirects, canonicals, hreflang, structured data, and sitemaps all stay intact. Core Web Vitals typically improve dramatically (LCP from 4s → 1.5s, CLS from 0.3 → 0), which is a Google ranking factor. Lighthouse SEO score goes from ~80 (Luma) to ~95 (Hyvä) by default. We do pre/post crawls (Screaming Frog) and report any URL diffs before cutover — no surprise drops.