Redirect Mapping Validator

Check a redirect map for chains, loops, self-redirects and duplicate sources before you deploy it.

Runs locally in your browser. Your input is never sent anywhere.

Redirect map — source and target, one pair per line

Or drop a CSV or TSV here, choose a file

Processed locally in your browser. The file is not uploaded.

What this checks

Paste or drop a two-column map — comma, tab or semicolon separated, with or without a header row. Quoted fields containing commas are handled. Nothing is uploaded.

Errors

Redirect loop — /a → /b → /a. The browser gives up and the page is unreachable.
Redirect chain — /a → /b → /c. Each hop costs latency and dilutes signals; point the first straight at the last.
Self-redirect — source and target are the same URL.
Duplicate source, different targets — which one wins is undefined.
Missing or malformed — an empty cell, whitespace inside a URL, or a non-http scheme.

Warnings

Several sources pointing at the same target, or an exact duplicate row.
Mixed relative and absolute forms in one mapping.
An HTTPS to HTTP downgrade, or a change of host.
A #fragment in the target — fragments are never sent to the server.
Source and target differing only by query string.
A path with no leading slash.

One limitation worth knowing

Chains are found by matching a row's target against other rows' sources, and that match is exact apart from lower-casing the scheme and host. A relative /b is not treated as the same URL as https://example.com/b.

That is deliberate. Stripping the host so both forms compare equal would make a domain migration — https://old.com/a → https://new.com/a — look like a self-redirect, reporting a serious error that does not exist. Missing a warning is better than inventing one, so when a file mixes both forms you get a mixed forms warning telling you chains may be hidden. Normalise the file to one form and re-run to be certain.