Website Replatforming SEO Checklist (Zero Traffic Loss)

Replatforming SEO success is measured in continuity, not launch day applause. Organic traffic drops usually come from broken redirects, lost metadata, accidental noindex, sitemap chaos, and template performance regressions. Use this checklist as a gate: if an item is red, you are not ready to cut over — regardless of design deadlines.

Before build: crawl the legacy site, export URL inventory with traffic and conversions, and classify keep / merge / retire. Draft the 301 map early and keep it in version control. Preserve high-value parameters intentionally or eliminate them with a plan. Screenshot critical SERP titles and schema types so “parity” is verifiable.

During build: match canonical rules, robots behavior, hreflang (if any), and structured data coverage on key templates. Staging must not leak into the index. Confirm pagination, faceted navigation, and soft-404 behavior. Performance budgets belong here too — a beautiful template that tanks LCP will bleed rankings after launch.

Launch window: deploy redirects first, then HTML. Validate a sample of top URLs returns 200 with expected canonicals. Submit updated sitemaps, keep the old sitemap temporarily if it helps discovery during transition, and watch Search Console coverage like a hawk for the first two weeks.

After launch: compare landing-page traffic, impressions, and conversions against a pre-launch baseline. Fix chains and loops immediately. Do not rewrite titles sitewide in week one unless you are repairing clear defects. Stability first, optimization second.

If a migration already damaged rankings, recovery is a project: redirect repairs, content restoration, and crawl budget cleanup. Send your old/new sitemap pair for a free audit and I will prioritize the highest-impact SEO risks.