Site migration QA
Preflight compares your before-migration crawl, your intended redirect map, and your after-migration crawl to find missing redirects, broken destinations, redirect chains and loops, lost indexability, wrong canonicals, and disappeared titles or content — before your customers and search engines find them for you.
Files are processed on our server and automatically deleted within 24 hours. Nothing is shared with anyone else.
Example report — migration.csv
Result: 2 errors · 1 warning · 1 info
Export a crawl of your site before migration, from any crawler or CMS export.
Prepare your intended old URL → new URL map and export a crawl after migration.
Upload all three CSV files.
Review the summary, download the full report, and fix what it finds.
Preflight is built around the specific ways a site migration goes wrong — not a generic diff tool. Every check below reflects a real migration failure mode, and rules that need data you didn't supply are skipped rather than guessed at.
Destinations that don't exist, that return an error, that redirect somewhere other than intended, or that chain through multiple hops or loop back on themselves.
Pages that were indexable and quietly became non-indexable after migration — or the reverse, exposing a page that was never meant to be public.
Destinations whose canonical tag points somewhere else entirely, or whose canonical simply disappeared where one used to exist.
Titles, meta descriptions, H1s, and page content that vanished or changed between the before and after crawl.
Old URLs that never made it into your redirect map, map entries that reference URLs your before-crawl never saw, and conflicting or duplicate mappings.
Crawl rows for the same URL that disagree with each other are flagged as ambiguous, not silently resolved by picking whichever row happened to come first.
During this beta, please don't upload highly confidential production files. Files are processed on our server, not purely in your browser — see the FAQ for exactly what that means.
A broken migration rarely announces itself. Traffic drifts down over weeks, not minutes, and by the time it's obvious in analytics the cause is much harder to trace back. A check that runs before launch catches the version of these problems that costs the most to fix afterward:
No. You provide the before-migration crawl, your intended redirect map, and the after-migration crawl as CSV files, from whatever crawler you already use (Screaming Frog, Sitebulb, a custom script, or a CMS export). Preflight never fetches a URL itself.
Briefly, yes. Your files are processed on our server to run the check and are automatically deleted within 24 hours, whether or not you download the report. During this beta, please don't upload highly confidential production data.
No tool can guarantee that. It checks exactly what your three files say — a redirect that looks correct in your data can still fail for reasons outside any CSV, like DNS, permissions, or a CDN rule. Preflight reports what the data shows; it doesn't crawl your live site or verify anything beyond it.
A URL from your before-crawl passes when it has a mapped destination, that destination exists and resolves correctly in your after-crawl, and nothing else about it — indexability, canonical, title, content — regressed. Everything else is bucketed into missing redirects, wrong destinations, redirect chains, loops, or other warnings.
No, and deliberately so. You supply the old-URL-to-new-URL map explicitly. A migration can involve domain changes, path restructuring, slug changes, or consolidation — guessing that correspondence would introduce ambiguity into almost every check.
Anything that requires actually crawling or rendering your site: JavaScript-rendered content, sitemap or robots.txt fetching, Search Console or analytics data, backlinks, Core Web Vitals, structured data, or visual regressions. It reports what your CSVs show, not what a live crawl would show.
No. It's vendor-neutral — it reads plain CSV with a small set of recognised column names, so it works with exports from most crawlers or CMS platforms without special integration.
Free during the beta. No account required to view the report.
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