Scan at scalePages with broken Link headers
Pages with broken Link headers
A per-URL report: one row per page that matches, over the pages a crawl reached.
What this report returns
Link response headers (RFC 8288) advertise machine-readable relationships (alternates, APIs, licensing) that agents can follow without parsing HTML.
These pages send a Link header parsers can't use: malformed syntax, a value missing its required rel, a duplicate or invalid rel, or an unresolvable target URI, so the advertised relationship is silently dropped.
How to fix it. Emit each value as <https://example.com/target>; rel="alternate", with quoted parameters and exactly one rel; the flagged columns show which rule each page breaks. (Relative / cross-scheme targets are valid and not flagged.)
The columns it shows
Every defect this technology can carry is a column in the grid, worst first, so nothing is hidden behind a filter you have to know to apply.
- Link Header Valid
linkHeaderValid - Link Header Findings
linkHeaderFindings - Link Header Offending Value Samples
linkHeaderOffendingValueSamples - Link Header Rels
linkHeaderRels - Link Header Malformed Syntax
linkHeaderMalformedSyntax - Link Header Missing Rel
linkHeaderMissingRel - Link Header Invalid URI
linkHeaderInvalidUri - Link Header Duplicate Rel
linkHeaderDuplicateRel - Link Header Invalid Rel
linkHeaderInvalidRel
About HTTP Link header
Relations declared in headers, readable without parsing the body.
Read how HTTP Link header is checked, including the specification it is validated against and a worked correct and broken example.
Running it
This report ships in the Lumar agent-readiness container and appears on any project it is linked to, on every crawl. See the whole set, or check a single URL with the scanner on this site, which runs the same code with no account.