Chapter 21 — Key Takeaways
A one-page reference. If you remember nothing else: inventory every URL, map each old one to its closest equivalent with a 301, verify the site is indexable at launch, and grade the migration on recovery — not on a launch week that never dips.
The one idea
A migration asks Google to move everything it knows about your old URLs onto new ones. Your entire job is
to make that transfer lossless — through a complete inventory, a disciplined 301 redirect map, a go-live
checklist whose first line prevents the accidental-noindex catastrophe, and close monitoring that tells a
normal dip from a real fire.
The five migrations, by risk
| Type | What changes | URLs change? | Risk | Classic failure |
|---|---|---|---|---|
| Domain change | the whole address | ALL | ★★★★★ | trust doesn't transfer; bad/missing map |
| Consolidation / restructure | which pages exist & where | MANY | ★★★★ | pages dropped without redirects |
| CMS / platform | URLs + templates + markup | MOST | ★★★★ | titles/links/schema silently lost |
| Redesign | look, templates, content | USUALLY NONE | ★★★ | staging noindex ships; content deleted |
| HTTP → HTTPS | the protocol | ALL (http→https) |
★★ | no redirects; mixed content |
Risk is about how much judgment the change needs, not how much changes. Change one variable at a time when you can.
The redirect discipline (the heart of it)
- 301, not 302. A 301 is permanent and passes the old URL's ranking signals to the new one; a 302 is temporary and tells Google to keep the old URL. Migrations use 301s.
- Map to the closest equivalent — never to the homepage. A redirect to an irrelevant page is treated as a soft 404 and passes no signals. The lazy homepage redirect destroys the exact equity you're moving.
- One hop, always. Redirect the original URL straight to the final URL. Chains (A→B→C) add latency, waste crawl budget, and can be abandoned after ~5–10 hops; loops (A→B→A) break the page entirely.
- Protect the pages with backlinks first. That's where off-site authority lives (Ch 22). A broken redirect there severs other sites' votes from your domain.
- Fix your own internal links. Point them at the new URLs directly; redirects are the safety net for external links and bookmarks, not a substitute for updating your navigation (Ch 15).
The go-live checklist (the operational core)
| Phase | The non-negotiables |
|---|---|
| Before (on staging) | Crawl staging (all 200s); redirect map loaded + tested (one hop); internal links updated; titles/headings/content/alt text/schema/hreflang carried over; new sitemap built; analytics + GSC installed; pick a LOW-traffic, non-Friday, non-peak launch window |
| At launch | ★ Remove the staging noindex/robots block and VERIFY the live site is indexable ★; redirects live at the instant of switch; correct canonical host; submit new sitemap; (domain move) use Change of Address |
| After (day 1, then daily) | Live-crawl for broken redirects/chains/404s; inspect crown-jewel URLs in URL Inspection; watch GSC coverage + 404s + Performance, analytics, rankings |
Normal vs. emergency (the judgment)
| NORMAL — wait & monitor | EMERGENCY — act today |
|---|---|
| Shallow-to-moderate dip, weeks 1–4 | Traffic off a cliff and still falling |
| Rankings wobbling ± a few positions | Crown-jewel rankings gone, not recovering |
| New URLs indexing as old ones drop | Whole site dropping out of the index |
| Dip bottoming / flattening | Indexed-page count collapsing |
| A handful of 404s you're fixing | A flood of 404s (redirects missing at scale) |
| Change of Address "processing" | Old URLs still indexed, new ones not (redirects broken) |
| Conversions holding | "Excluded by noindex" climbing ← the launch catastrophe |
A rollback in week 2 makes Google reprocess everything again — you migrate twice. Wait out the left column; fix the right column tonight.
Rules of thumb
- You migrate a spreadsheet, not a website. If a URL isn't in the inventory with a decision, it's lost.
- Baseline before you touch anything — you can't measure a dip or a recovery without a before-picture.
- Redirects are necessary, not sufficient. They preserve equity; they can't make a worse new page rank like a better old one.
- Verify, don't trust. "The
noindexis gone" means you loaded a live page and checked, not that someone said so. - Grade on recovery, not on a flat launch week. Even textbook migrations dip; the question is how fast and to what level they come back.
- Check the calendar. A dip that coincides with a confirmed core update (Ch 6) may not be your migration.
- Diversify traffic. Email, direct, social, and brand are the cushion for the week you move the ground on purpose.
What you can do today
Open Search Console → Performance, set the range to 12 months, export by Page, and sort by clicks. That ranked list is the spine of any migration plan — the crown jewels you would defend first. Then run one of those URLs through URL Inspection and confirm it's on Google. Those two habits, built on calm days, are the ones you'll run under pressure on launch morning.
Where this goes next
→ Chapter 22 opens Part IV (Authority & Link Building): why Google trusts one site more than another, the PageRank idea that started it all, and what makes a link valuable — the off-page authority your redirect map exists to protect.