Free Broken Link Checker Tool — Find & Fix 404s to Improve SEO
A complete guide and ready-to-use widget (HTML/CSS/JavaScript) to scan your site for broken links. Works great on Blogger & WordPress.
Broken links (404s) hurt user experience and SEO. This page explains what broken links are, why they matter, how to fix them, and provides a simple, copy-paste widget you can embed on your blog to scan links quickly. Scroll to the “Broken Link Checker” section to use the tool instantly.
Introduction — Why Broken Links Matter
When a user clicks a link that leads to a page that no longer exists, they see a 404 page. These broken links reduce trust, cause higher bounce rates, and send negative signals to search engines. Removing or fixing broken links is a simple but powerful way to improve your website’s SEO, accessibility, and visitor satisfaction.
What Is a Broken Link?
A broken link is any URL that does not load a valid resource. Typical causes include:
- Page was deleted or moved without redirect
- Typo in the URL
- External site removed the page
- Temporary server error or domain expiry
SEO & UX Impact — The Real Cost
Search engines crawl your site. If crawlers encounter many broken URLs, they’ll consider the site less maintained. Visitors encountering 404s are likely to leave quickly, increasing bounce rate and decreasing time-on-site — both negative ranking signals.
Benefits of fixing broken links
- Improved user experience — visitors find what they expect
- Lower bounce rate and increased engagement
- Cleaner site for crawlers — better indexing
- Opportunity to recover lost backlinks by redirecting them
How the Free Broken Link Checker Works (Widget Overview)
This widget is built with pure HTML, CSS and JavaScript — no server required for basic pages on the same domain. It fetches the target page, extracts links, and performs HEAD requests to get HTTP status codes for each link. Results are displayed in a simple list showing OK vs Broken links.
Try the Broken Link Checker (Widget)
Important: If your target website or external links block cross-origin requests (CORS), the widget may not be able to check some links from the browser. See the note below about CORS and workarounds.
How to Use This Widget on Blogger (Step-by-step)
- Open your Blogger dashboard → Pages (or Layout → Add Gadget → HTML/JavaScript).
- Create a new Page (or Gadget). Switch to the HTML view (not Compose).
- Paste the entire HTML below into the HTML editor (or paste the widget portion if you only want the tool).
- Save and Publish the page. The widget will appear on your page.
How to Use on WordPress
- Open WordPress Admin → Pages → Add New
- Add a Custom HTML block and paste the widget HTML/JS into the block.
- Publish the page. If using caching plugins, clear cache after publishing.
Limitations & CORS — What You Must Know
The browser’s security model sometimes blocks JavaScript from requesting resources on other domains (Cross-Origin Resource Sharing). If the target site or the link’s domain doesn't permit cross-origin HTTP HEAD/GET requests, the widget may fail to get a status code for that link. You will see an error or “Unreachable”.
Workarounds
- Use a server-side proxy: host a tiny serverless function (Netlify Functions, Vercel Serverless, Cloudflare Worker, or your own server) that performs the requests. The page calls your serverless endpoint which then fetches links and returns statuses.
- Host the checker on the same domain: if the page and the target site are on the same origin, CORS won't block the checks.
- Allowlist your origin: if you control the target domain, configure response headers to allow requests from your page origin.
Advanced Tips — Pro Workflow
For bigger sites (hundreds of pages), use a server-side crawler that collects internal links and then runs status checks asynchronously. The client-side widget is ideal for quick single-page checks, small blogs, or manual SEO audits.
Exporting Results
The widget supports exporting results as CSV so you can keep a record, share with developers, or schedule fixes.
Yes — the widget code below is free to use and modify.
Q. Does this check external links too?Yes, it will attempt to check external links too but may hit CORS restrictions for some domains.
Q. Can it crawl multiple pages of my site?The browser widget checks one page at a time. For whole-site crawling, use a server-side script or the single-file Python tool (I can provide it if you want).
Conclusion
Fixing broken links is an underrated but powerful SEO tactic. Use this free widget to quickly identify and fix 404 errors on your pages, and consider server-side crawling for complete site audits. Keeping your site free of broken links improves user experience, lowers bounce rate, and helps search engines trust your site more.
Tip: If some links show as Unreachable due to CORS, consider using a small serverless proxy. Ask me and I can provide one-line serverless code.