Ask most teams how many external links their site has, or which domains they point to, and you'll get a shrug. TechySEO catalogs every outbound link, whether it's pointing to an HTML page, an image, a PDF, a script, or a stylesheet on someone else's server, and checks that the destination is still there and still something you'd want your name next to.
It runs both directions. Link to authoritative, relevant sources and you borrow some of their credibility. Link to something spammy, penalized, or just dead, and you're telling both users and search engines that nobody's been checking the citations in a while.
The part that catches people off guard is how this happens without anyone doing anything wrong. A study you cited three years ago moves to a new URL. A small partner site shuts down. A domain you linked to gets dropped, then bought by an entirely different company, and now your "helpful resource" link points at a parked page or worse. None of this throws an error in your CMS. It just sits there until someone clicks it, or until you actually go looking.
TechySEO checks every external destination at crawl time, so "where does this link actually go right now" has an answer that doesn't depend on someone clicking through it by hand.
By file type, by destination domain, by current status. The stuff you'd need a spreadsheet and a free afternoon to build manually.
Run the audit and find the dead citations, the HTTP holdouts, and the one domain you didn't realize you were linking to forty times.
