SEO-15 · SEC. 07 SEO & GEO

Zero-Loss Redirect Map for a Site Migration

Map every old URL to its new home, then loop until there are no chains, loops, or lazy homepage dumps.

FORMAT: loop
DIFFICULTY: advanced
TIME: 30 min
TOOLS: universal
MODELS: any
COPIES: 0 so far

When to use this

You're changing URL structure, merging sites, or replatforming, and every old URL needs a 301 target before launch. Use this before the migration ships. A redirect map written by hand the night before is where rankings go to die.

The pattern

Pastes as plain text

Below the line are two lists: every old URL on my site, then a line
reading "NEW URLS:", then every URL that will exist after the migration.

Build a 301 redirect map in this loop:
1. Match each old URL to the single best new URL by slug, path segments,
   and apparent topic. Tag each match HIGH, MEDIUM, or LOW confidence.
2. Move every LOW match to a "needs human decision" list with your top 2
   candidate targets and one line on why you couldn't decide. Never guess
   on a LOW.
3. Run these checks on the map:
   - Every old URL appears exactly once.
   - No target is itself an old URL that redirects (that's a chain).
   - No pair of rules sends A to B and B back to A (that's a loop).
   - No target is the homepage unless the old page truly has no
     equivalent. Flag every homepage target as suspect.
   - No old URL is silently missing from both the map and the
     needs-human list.
4. If any check fails, fix the map and run all of step 3 again. Repeat
   until every check passes in a single pass.
5. Output: (a) the passing map as CSV with columns old_url,new_url,status
   unless I name a server format like nginx or a Next.js redirects block,
   (b) the needs-human list, (c) counts: total old URLs, HIGH, MEDIUM,
   needs-human, homepage-flagged.

Paste the old URLs, then "NEW URLS:", then the new URLs, below this line:

Real example output

Checks: pass on iteration 2 (iteration 1 found 3 chains where a target
was itself in the old list, and 1 A->B->A loop between /pricing and
/plans — all re-pointed to final destinations).

old_url,new_url,status
/blog/2023/invoice-tips,/resources/invoice-tips,301
/features.html,/features,301
/docs/api/v1/auth,/docs/api/authentication,301
/pricing-2024,/pricing,301

Needs human decision (4):
- /blog/founder-interview-2022 -> /about/team OR /resources/archive
  (topic exists in neither; page reads as PR, not evergreen content)
- /labs/beta-signup -> /product/early-access OR drop with 410
  (beta program appears discontinued in the new URL list)

Counts: 312 old URLs. 268 HIGH, 40 MEDIUM, 4 needs-human,
2 homepage-flagged (both legacy campaign pages with no new equivalent).

Why it works

Redirect maps fail on structure, not on individual picks: chains leak equity hop by hop, loops kill pages outright, and "just point it at the homepage" is a soft 404 in Google's eyes. Making the model re-run the full check suite after every fix, instead of patching one error and declaring victory, is what catches the second-order breakage a single pass always misses.