Web Tool Bench's Broken Link Checker reads every link on a page, internal and external, and requests each one, up to forty per run. It reports the status code that comes back: 404 for a missing page, 410 for one removed on purpose, 5xx server errors that are often temporary, 403 that is usually a bot block, and 0 when the host did not answer at all. It uses HEAD requests, so nothing is downloaded. The page explains which results to fix first (internal links, because they waste crawl budget and can orphan pages) and why a 403 should be opened in a browser before you delete the link. Free, no sign-up, and nothing you enter into the checker is stored.
Most online tools give you an answer and stop there: a status code, a red cross, a block of directives, and no idea what to do next. I built Web Tool Bench around that second part. Every tool page has a worked example and explains what the result means and what to fix first. For broken links, that means separating real 404s from bot-filtering 403s before you delete anything.