Give it a feed URL (or a website that links to its feed) and get a JSON report: detected format, XML well-formedness, required and recommended elements, date formats, duplicate IDs, enclosures and basic podcast fields. Coded issues with line numbers, a grade (A+ to F) and a score out of 100. Handles RSS 2.0, Atom 1.0, RSS 1.0 and JSON Feed. For CI checks and publishing pipelines.