Detect broken links and 404 errors on your website
Enter the address of a website below. Bye404 follows every internal link on the site, requests each address, and reports the ones that answer with a 404 or another error, together with the page the faulty link was found on. The scan is free, requires no account and installs nothing.
Analysing the site, this can take a few minutes on a large website. Please leave this page open.
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What Bye404 checks
The crawler starts from the address you give it and behaves like a search engine robot. It reads the page, collects every internal link it contains, requests each of those addresses in turn, and repeats the process until it has covered the whole site or reached the limit of 2500 pages.
For every address it records the HTTP status code returned by your server. Anything in the 4xx or 5xx families is reported as broken, with one important exception: a 403 Forbidden usually means the server is blocking automated requests rather than that the page is missing, so those are not counted as errors. The same applies to a 429 response, which simply means the server asked the crawler to slow down.
The report is deliberately built around the source page rather than the broken address. Knowing that /old-article.html returns a 404 is only half the information. What you actually need is the list of pages containing the link, because those are the files you have to edit.
Why broken links matter
They waste the attention search engines give you
Search engines allocate a finite amount of crawling to each site, what Google calls the crawl budget. Every request spent on an address that leads nowhere is a request not spent discovering or refreshing your real content. On a small site this is invisible. On a site with thousands of pages it directly slows down how quickly new content appears in search results.
They break the internal structure of your site
Internal links are how ranking signals move between your pages, and how visitors travel from one subject to a related one. A broken link is a dead end in that network. The page it was supposed to lead to loses the signals the link was passing along, and often becomes harder for crawlers to reach at all.
They cost you visitors
Someone who clicks a link and lands on an error rarely tries a second route. They go back to the search results and open a different site. On a commerce site the effect is immediate and measurable; on an editorial site it shows up as a rising bounce rate that nobody can explain.
They signal an abandoned site
A site with visibly broken links reads as unmaintained, which changes how much a reader trusts what it says. This is not something an algorithm measures directly, but it is something every human visitor notices.
How to use the results
Once the scan finishes you have a list of broken addresses and, under each one, the pages containing the link. Work through it in this order:
- Internal links first. These point from your pages to your pages, so they are entirely under your control and always worth fixing.
- Check whether the address is simply wrong. A large share of 404 errors come from a typo, a missing extension, or an uppercase letter in a path served case sensitively. In those cases the destination is fine and you only need to correct the link.
- Redirect what moved. If the content lives at a new address, add a permanent redirect from the old one. Do not redirect everything to your homepage: search engines treat that as a soft 404 and visitors find it more confusing than the error itself.
- Declare deliberate removals. Content you retired on purpose should return a 410 Gone rather than a 404, which clears the address from the index faster.
- Rescan. A second pass confirms the repairs and catches the errors introduced while making them, which happens more often than expected.
Our step by step guide on how to fix a 404 error covers each of these decisions in detail, with the rules to write in your .htaccess file.
Common questions
Do 404 errors get my site penalised?
Not directly. A page returning 404 is simply dropped from the index over time. The damage is indirect and comes from wasted crawling, lost internal linking and visitors who leave. It is real, but it is not a penalty attached to the code itself.
Why does the scan report a page that works in my browser?
Usually because the server treats automated requests differently from browsers, which produces a 403 or a timeout for the crawler while a human sees the page normally. Rate limiting and pages behind a login produce the same effect.
Why are some of my pages missing from the report?
A crawler can only reach what is linked. A page nobody links to, sometimes called an orphan page, is invisible to it even though the address works perfectly. If a whole section is absent from the report, check whether anything actually links to it.
Are my results stored?
No. The state of a scan exists only while the scan is running and is deleted when it ends. The results are displayed in your browser and are not kept afterwards, so copy anything you need before leaving the page.
More answers are on the frequently asked questions page.
Learn more
HTTP status codes explained gives the full reference for every response you will see in a report, from 301 to 503, and explains when to use a 410 rather than a 404.
Broken images and soft 404 errors covers the failures that no status code reveals: images lost to a case sensitive filesystem, hotlinked files that disappeared, and error pages that wrongly return 200 OK.
The redirect checker is the companion tool for what this page cannot show you: a redirection is not an error, so it never appears in a broken link report, even when three of them stack up in front of every page.
The glossary defines crawl budget, canonical URL, orphan page, redirect chain and the other terms used across these guides.
Once your internal links answer correctly, a sitemap tells search engines which addresses to keep. sitemapauto.com crawls a site and generates the XML file for you, free and without an account.