Frequently asked questions
The questions below cover both the tool itself and the broader subject of broken links. If your question is not answered here, you can write to us.
About 404 errors
Do 404 errors hurt my search engine rankings?
Not directly, and this is widely misunderstood. A page that returns 404 is simply removed from the index over time, as Google describes in How HTTP status codes affect Google's crawlers. What harms you is the indirect effect: internal links pointing at nothing waste the crawling effort search engines spend on your site, visitors who hit an error leave sooner, and a site with many broken links looks unmaintained. The pages that lost their inbound internal links also lose the ranking signals those links were passing along. So the damage is real, but it comes from the surrounding effects rather than from a penalty attached to the code itself.
How many 404 errors are acceptable?
There is no threshold to respect. What matters is the type. Broken internal links, meaning links inside your own pages that point at your own missing pages, should be at zero, because they are entirely under your control. Errors caused by external sites linking to you incorrectly, or by visitors mistyping an address, will always exist and are not a problem as long as those visitors land on a helpful error page.
Should I redirect every 404 to my homepage?
No. It looks like a tidy solution and it is one of the worst habits in web maintenance. The visitor who wanted a specific article arrives on a homepage with no explanation and usually leaves. Search engines recognise a redirect to an unrelated page as a soft 404 and treat the address as missing anyway, so you gain nothing. Redirect to a genuinely equivalent page when one exists, and otherwise let the 404 happen on a well designed error page.
What is the difference between a 404 and a 410?
A 404 means the address does not correspond to anything, without saying whether it ever did. A 410 means the content existed and was deliberately removed. Search engines drop a 410 address from the index faster because the removal is declared intentional. Use 410 for content you retired on purpose and 404 for everything else. The status code reference covers both in more detail.
Why do some pages return 403 instead of 404?
A 403 means the server found the resource but refuses to serve it. Sometimes this is a genuine permission problem, but very often it is a protection mechanism reacting to an automated request. Many hosts block anything that does not look like a normal browser, so a link checker receives a 403 for a page that works perfectly when a human visits it. This is why our tool reports 403 responses separately rather than counting them as broken links.
My page exists but the checker reports an error, why?
Three causes account for almost all such reports. The server may be rate limiting automated requests, in which case the same address answers correctly a few minutes later. The page may be behind a login, which no external checker can pass. Or the page may take longer than the timeout to respond, which is itself worth investigating since real visitors are waiting just as long.
How often should I check my site?
After any significant change to the structure of the site, and otherwise every two or three months. Broken links accumulate slowly: internal pages get renamed, and external sites you link to disappear without telling you. A short scan after each update catches the errors you just introduced, when the change is still fresh in your mind and easy to undo.
About the Bye404 tool
Is the service free?
Yes. There is no account to create, no subscription and no software to install. You enter an address and the scan starts.
How many pages can be scanned?
The crawler explores up to 2500 pages per scan, which covers the great majority of sites. The scan stops earlier if it runs out of internal links to follow, which is the normal ending for a smaller site.
Is there a usage limit?
Each address is allowed 20 scans per 24 hours. The limit exists so that the service stays responsive for everyone and so that the crawler does not become a nuisance to the sites being tested. It resets automatically.
Can I scan a site I do not own?
Technically yes, and the tool is often used that way to evaluate a site before taking over its maintenance. Keep in mind that a crawl generates real traffic on the target server, so scanning a site repeatedly without a reason is inconsiderate.
What is the difference between the three tools?
The link checker follows the links between your pages and reports pages that do not answer. The image checker looks at the images and documents your pages reference and reports the files that are missing. The redirect checker reports the addresses that answer with a redirection, and separates harmless ones from chains, loops and redirects landing on a dead page. If your site has many pages, start with the link checker, since a missing page usually takes its images with it.
Does the scan slow down the site being tested?
The crawler is deliberately paced and requests a small batch of pages at a time rather than flooding the server. On a normally configured host the load is comparable to a handful of simultaneous visitors.
Can it check links pointing to other websites?
The crawler follows internal links only, in order to map your site without wandering across the whole web. Outgoing links to other sites are worth monitoring too, since they break without any warning, but that is a different kind of scan.
Do you keep the results of my scan?
No. The state of a crawl is held only while the scan is running and is deleted when it finishes or when you stop it. The results are displayed in your browser and are not stored afterwards, so copy anything you want to keep before leaving the page. Our cookie information page and terms of use describe what the site does with data.
Why does the scan stop before reaching my last pages?
Usually because those pages have no internal link pointing at them. A crawler can only reach what is linked, so an orphan page is invisible to it even though it exists and is perfectly reachable by anyone who knows the address. If a section of your site is missing from the report, check whether anything actually links to it, and consider adding it to your navigation or to a sitemap.
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