Checklist: the pre-launch SEO migration list that prevents a traffic crater

Checklist: the pre-launch SEO migration list that prevents a traffic crater
I ran two real migrations using Screaming Frog + Ahrefs. The damage always comes from the same 5 missed items.

Do ALL of these before flipping DNS:
— Crawl the OLD site, export every indexable URL. This is your redirect source of truth.
— Map old → new 1:1. Redirect to the closest equivalent page, never blanket-redirect to homepage.
— Use 301s only. Check for chains (A→B→C) — collapse them to A→C.
— Carry over titles, meta, canonicals, and schema. Re-crawl staging to confirm none dropped.
— Match the OLD internal link structure on key pages — orphaned new pages tank.

Then post-launch:
— Re-crawl live, diff against the old export. Any old URL not 301'd = a leak.
— Submit the new sitemap and watch GSC coverage daily for 2 weeks.

Screaming Frog:
➕ Old-vs-new URL diff + redirect mapping in one tool
➖ Mapping is manual on large sites
Ahrefs:
➕ Shows which old URLs had links worth preserving
➖ Separate step from the crawl

Pick this if you're changing domain, CMS, or URL structure. Skip the panic — done in this order, migrations rarely lose traffic.