Original lab · Website migration

Can a redirect map stay one-to-one when routes look alike?

This compact benchmark separates the easy case—identical paths on a new origin—from an intentionally ambiguous summer-sale inventory. It is designed to expose where automated similarity must stop and owner review must begin.

Worked sample, not a live result.The observations below come from the checked-in synthetic fixture text, not from a current browser run, production crawl, Search Console property, or deployed redirect configuration. Run the workbench to create a fresh result and receipt.

Question and decision rule

The benchmark asks whether every old URL has exactly one defensible destination. The fixture is not trying to prove SEO success. A mapping is ready for implementation only when a reviewer can explain every destination, collisions are resolved, and the actual server syntax has been tested outside this page.

Expected clear case

Four old URLs and four new URLs share the same paths across different synthetic origins. Exact path equality provides a reviewable candidate for each source.

Expected review case

Three old summer-sale routes compete for two similar destinations. The benchmark intentionally supplies no content IDs, analytics, canonicals, or owner overrides, so a one-to-one answer cannot be asserted from strings alone.

Method

  1. Normalize scheme, host, path, query, and trailing-slash representation without inventing content equivalence.
  2. Compare exact path candidates before weaker token or route-shape similarity.
  3. Count sources, destinations, unmatched routes, and destinations claimed by more than one source.
  4. Send every ambiguous or low-confidence mapping to a named owner; do not convert it into a production rule automatically.
  5. After approval, test the generated rules against the real edge or web server and monitor old and new URLs.

Repeatable fixtures and SHA-256 evidence

These files are synthetic and use the reserved .test domain. From the repository root, run the command exactly as shown. The links belong to this local review build and are not claimed to be live on the public site.

shasum -a 256 app/fixtures/flagship-editorial-20260713/website-migration/*.txt
  • pass-old.txt72bfd81206bc4d91dc6c3a0828f989fcd8aafff1d2fa078c2ae0d48e88b49afd
  • pass-new.txt34ece7b122278a88628e6807b73545db2e75914147d7a82fa9cdd1a62843c2fa
  • review-old.txt08cfe8f7deff7fbb0d5ad3218ba26d243b0b19154a0f9b468200a944e7d13127
  • review-new.txtfb07a6ca038a259be64c5510988f27eb441693fd5f8485d4c0dfcca9030d2b17

Deterministic fixture observations

CaseOld URLsNew URLsWhat the fixture provesDecision
Same-path move44Every old path has a same-path destination in the supplied inventory.Candidate for owner approval
Ambiguous sale routes32The inventory alone is insufficient for a defensible one-to-one map.Manual review

This table is a direct count of fixture lines. It does not claim how the live workbench will score confidence, because scoring logic and input context can change. A fresh export is the evidence for an actual run.

Limits, privacy, and safe interpretation

Limits

  • No live crawl, DNS change, redirect deployment, ranking forecast, or traffic guarantee.
  • No server logs, inbound-link data, content IDs, hreflang graph, or authenticated route evidence.
  • String similarity cannot decide whether two pages serve the same user need.

Privacy boundary

Use public, staged, synthetic, or redacted inventories. Do not include preview tokens, credentials, customer identifiers, or authenticated URLs. The canonical tool processes pasted or selected inventories in the browser, but a trusted device and approved handling policy are still required.

Official sources

Corrections and reproducibility

FastTool is the publisher responsible for this page. Report a wrong count, stale source, ambiguous instruction, or fixture/hash mismatch to [email protected]. Include this URL, the exact statement, your evidence, and the change you recommend. Material corrections are recorded in the changelog.

Reviewed 2026-07-13 · Editorial fixture set flagship-editorial-20260713.