We have run thirty-one migrations since 2016 and have not yet permanently lost a client's organic traffic. Not because we are unusually clever, but because we follow the same tedious sequence every time.
1. Inventory before anything else
Every URL on the current site, from a crawl and from server logs and from analytics and from Search Console. Those four sources never agree, and the discrepancies are where the risk lives. Each URL gets scored on organic sessions, conversions, inbound links and internal link depth.
2. Decide what is not coming across
A migration is the only good opportunity to retire dead weight. Pages scoring zero on all four measures are candidates for removal — but that is a decision made explicitly, documented, and signed off, not an accident discovered three weeks later.
3. Write the redirect specification
One row per old URL, one target per row, no chains, no redirects to the homepage as a catch-all. On a 4,200-URL catalogue this takes days. It is the single highest-value document in the project.
4. Crawl the staging environment
Crawl pre-production with authentication and compare against the live crawl: titles, headings, canonicals, structured data, internal links, response codes. Every difference is either intentional or a bug, and both need a name against them.
5. Launch window and rollback trigger
Launch early in the week, never on a Friday, never during a seasonal peak. Define in advance what the rollback trigger is — ours is typically a 25% drop in indexed pages or a 40% drop in organic sessions sustained over 72 hours — and make sure the hosting team knows how to execute it.
6. The first 48 hours
Hourly log monitoring for crawler response codes, immediate resubmission of sitemaps in both Bing Webmaster Tools and Search Console, and a manual spot-check of the top hundred URLs by value. Expect a dip. A nine-to-twenty-day dip is normal; a dip that is still deepening in week four is a problem.
7. The post-mortem
Written, circulated, and honest about what surprised us. Ours have been the source of most improvements to this playbook.
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