What this tool checks
The checker loads your page, extracts every <a href> pointing at the same site (up to 30), and requests each one, reporting the HTTP status it gets back. Anything 400 or above is flagged as broken; connection failures and timeouts show as ERR. Redirects (3xx) are reported as-is rather than followed — a redirecting internal link is not broken, but it is a link you should update to the final URL. The scan deliberately stays same-origin: external links rot too, but internal ones are entirely your fault and entirely your fix.
Why broken internal links matter
Internal links are how both users and crawlers move through your site, and how ranking signals flow between your pages. Every broken one is a triple loss. Users hit a dead end — and a visitor who lands on a 404 from your own navigation rarely tries again. Crawl budget burns — Googlebot requests the dead URL, gets nothing, and that visit is spent. And equity evaporates — a link from your high-authority homepage to a 404 passes its value into the void instead of boosting a real page. Broken links also compound quietly: a renamed blog category or a CMS migration can break hundreds of links at once, and nothing alerts you unless something is actively checking.
How to fix what the scan finds
Work down the list by status. 404s: if the target moved, update the link to the new URL; if the content is gone, remove the link or redirect the old URL to its closest living relative — never blanket-redirect to the homepage, which Google treats as a soft 404. 5xx errors: the page exists but the server choked — check whether it is a one-off (re-run the scan) or a route that consistently fails. ERR entries:usually a typo'd subdomain, an expired certificate, or a dropped DNS record. 3xx entries: edit the link to point at the redirect destination and reclaim the wasted hop. Then fix the source of truth, not just the symptom: broken links usually come from templates, navigation menus or old content imports, so one template fix often clears dozens of instances.