Broken link checker

Why broken links matter

A link that leads to a 404 is a dead end for a visitor and for a search engine. Google finds pages by following links — its documentation says it "uses links as a signal when determining the relevancy of pages and to find new pages to crawl" (Google: link best practices) — so a broken link wastes the visit and the signal.

What this checker does

It reads one page, finds every <a href> the way our crawler does, and asks each address what it answers — up to 100 links, several at a time, within a time limit. Whatever did not answer in time is listed as not checked, with the count, rather than guessed at.

• Broken means the address answered 404, 410 or another "not here" code.
• Refused us (401, 403, 429) is not the same as broken: many sites turn automated checkers away, and the link may work in a browser.
• Redirects work, but a link to your own page that redirects costs an extra request every time. Link to the final address.
• robots.txt is obeyed for every link, as our crawler obeys it; a link it forbids is listed as not checked.

Next: follow a redirect hop by hop, or read about backlinks and broken links.