Migration risk comes from changing signals together
A move from WordPress or a JavaScript application to Astro-generated HTML can improve control and performance. It can also change URLs, internal links, rendered content, canonicals, metadata and analytics in one release. Search engines then need to understand both the new pages and their relationship to the old property.
Google advises careful planning for site moves, while migration “hangovers” are commonly associated with redirect errors, noindex directives and SEO being involved too late. Treat the project as a signal-preservation exercise, not just a redesign.
Before launch: build the evidence baseline
Crawl the existing site and combine that inventory with sitemaps, analytics, Search Console, backlink destinations and business-critical routes. Classify each URL as retain, consolidate, redirect or retire. Preserve pages with real demand or external authority unless there is a documented reason to change them.
Create an explicit old-to-new redirect map. Avoid sending unrelated URLs to the homepage or chaining through previous migrations. Record current titles, descriptions, canonicals, hreflang, structured data, status codes, content and internal-link depth so the new templates can be compared.
Pre-production: validate the actual static output
Test generated HTML, not only the development interface. Confirm that every indexable page has a unique title and H1, self-referencing canonical, correct robots directive, crawlable links and complete content in the response. Validate sitemap membership, hreflang reciprocity, structured data and error handling.
For a static deployment, check that edge rules preserve status codes and redirects. A visually rendered 404 that returns 200 can create soft-error problems. Ensure build pipelines cannot publish draft or environment-specific canonicals.
Launch: keep the change observable
Deploy redirects at the same time as the new URLs. Submit updated sitemaps, verify analytics and conversion events, and inspect representative pages from every template and market. Monitor logs, crawl errors, indexing, impressions, branded journeys and revenue indicators daily during the first phase.
Do not judge the migration from aggregate traffic alone. Segment changed and unchanged URLs, market, template and query type. That reveals whether a specific mapping or template is responsible for a decline.
After launch: fix causes before adding more change
Keep redirects for as long as users and external links may rely on them. Update important internal and external destinations where possible, but do not remove redirects immediately afterward. If visibility falls, compare the new output against the baseline before rewriting content or launching another redesign.
Our Technical SEO and Casino SEO Audit workflows provide migration acceptance criteria, launch validation and post-launch monitoring.