Dead Link City - Comparison of Link Checkers
A number of Dead Link Checkers were used to analyse the DeadLinkCity.com site. This site contains examples of many different types of broken link, both in HTML and CSS style sections. In addition it tests whether a link-checking tool follows directives in the robots.txt file, telling the tool to ignore a link which would otherwise be reported as bad. There are 74 known bad links in DeadLinkCity.com, and one additional link which should not be reported if the tool obeys robots.txt directives.
The tools that were tested consisted of five online checkers and three downloadable programs. The perfect score is 74 - the closer the number of reported errors is to 74, the more accurate the tool is.
|Tool||Format||Errors reported||Obeys robots.txt?||Notes|
|2||Web Link Validator||Download||60||No|
|3||Xenu Link Sleuth||Download||57||No|
|4||LinkTiger.com||Online||45||Unknown||Requires Credit Card|
|9||Screaming Frog||Download||Unknown||Unknown||Requires Java|
A free online tool, with an optional autochecker subscription for automatic checking of up to 100 websites with up to 1,000,000 links.
This tool located all 74 links in the test site, and was the only one of the tested tools to respect the robots.txt directive. The error report showed the HTML error code for each invalid link together with the URLs of the link and the page containing it, and any associated text to assist in locating the link within the HTML source.
This appears to be the most accurate and thorough link checking tool on the market today.SEMRush.com - site audit
SEMRush requires free registration, using an email address to confirm your identity, before use. Once registered you can click the button 'Create my first project', choosing project domain www.deadlinkcity.com and project name DeadLinkCity.
The dashboard shows various tools - site audit, position tracking, SEO ideas and social media tool. Link checking is part of the site audit.
The comprehensive configuration options in Site Audit allow you to control the scan - you can:
- Limit the number of checked pages,
- Specify a particular subdomain,
- Determine the user-agent to be used,
- Set the crawl-delay (default 1 second between pages, but can respect robots.txt crawl-delay),
- Set URL filters for pages to specifically exclude or include,
- Specify URL query parameters to remove before checking a URL,
- Set the scan time/frequency (day of week, or once only).
When the scan is set up, click 'start audit'. The report gave DeadLinkCity.com a 50% health score, claiming to have scanned 102 pages (links) of which 52 had issues, 41 were broken, 4 were redirects and 5 were healthy.
Getting to the actual errors involves drilling into various sections of the report, and could be made more intuitive.
The tool found all the 4xx and 5xx HTML status errors and missing images, but failed to find bad links within CSS style, or within any HTML elements other than <IMG> and <A> tags. It did not appear to respect the 'allowed' directive in robots.txtDrLinkCheck.com
To use this free online link checker, enter the URL to check and click 'Start'. The scan runs quickly, showing a list of good and bad links with 12 to a page.
The summary showed 50 links checked - 49 internal and 1 external - with 46 broken links detected. For each link there was a tick or a cross to indicate whether it was broken or not, together with the URL of th elink and the page it was found in. Hovering the mouse over a broken link indicated the HTML status code (404, 500, etc.)
This tool found all 4xx/5xx errors, but missed bad CSS links and most bad HTML links in elements other than <A> tags. It ignored the robots.txt directive.BrokenLinkCheck.com
This free online tool offers checking of up to 3000 pages, with no limits on the number of links within those pages. To check larger sites, you are asked to contact the authors for a quote.
Scanning is simply a matter of enter the URL to check (www.deadlinkcity.com) - you are then asked to fill in a captcha, and are given the option to show distinct broken links only, or all occurrences of each broken link. Clicking on 'Find broken links now' starts the scan.
The report showed the URL of each bad link, its HTML status code, and the URL of the page containing the link. It also linked to a source-code view highlighting the line containg the bad link.
However only 17 bad links were reported - the tool failed to spot links with an HTML error code above 414, missing images, redirections, or errors in CSS or HTML elements other than <A> tags.PowerMapper.com - SortSite
PowerMapper SortSite is a downloadable application with a free online trial version that can scan 10 pages of any public website.
Entering www.deadlinkcity.com and pressing 'test site' ran the scan, which said there were 18% pages with issues. The online report was a tabbed display whose navigation was not immediately obvious - however there was quite a lot of information available in addition to the bad links, including advice on usability, compatibility, privacy and standards compliance.
The bad link information was rather sparse - only 9 bad links were reported (those with HTML status codes betwen 400 and 407). Perhaps this was a result of using the free tool. Each link showed the URLs of the bad link and the page it was referenced. A line-number linked out to an HTML source view of the page with all errors and warnings interspersed within the HTML.LinkTiger.com
Link Tiger is a paid service with a free trial. After entering the URL to check, an account has to be set up using an email address and password. The scan then started, and shortly afterwards an email arrived saying:
"Your website(s) currently have 57 links, with 45 broken links (broken link report will be accessible in the next step). We pre-selected the Large subscription based on the amount of links. Please visit LinkTiger Signup and fill in your credit card information to activate your 15 Day Free Trial. Your credit card will not be billed and you can cancel anytime. "
We were not prepared to hand over credit card details at this stage, so it is unclear which dead links were identified by Link Tiger - however it seems to have missed many of them.Xenu Link Sleuth
Xenu Link Sleuth has been around for some time, and is rather quirky but quite effective. It is a downloadable program which needs to be installed on a WIndows PC. It does not run on Mac or any OS other than Windows.
On starting Xenu Link Sleuth, select the File->Check URL menu option and enter the URL in the dialog that appears. There are options to list URL patterns to include or exclude from the scan, and the 'more options' button allows you to fine-tune the data that will be presented in the final report, as well as a few scanning parameters. Clicking 'OK@ then starts the scan.
The scan is very fast. When it finishes, there is a box asking for FTP details - this would be used to check for 'orphan' files on the server which are not linked in the HTML, but this feature is not needed so the box can be cancelled. A browser window is then opened with the report.
The report itself contains a list of valid links, suitable for making a sitemap, and the broken links organised first alphabetically, and then by the page they are found on.
Xenu Link Sleuth identified 57 bad links on DeadLinkCity.com - it failed to spot missing images in CSS, and certain HTML elements went unchecked (including audio, video and some form data). It did not respect the directive in the robots.txt file.Web Link Validator (RelSoftware)
WebLinkValidator is a downloadable application with a 30-day trial period. It appears to be WIndows only. The trial version is limited to 500 links.
The QuickStart menu option allows you to enter a URL to be scanned. There are options to restrict the scan to one page, to check external links, and to run a spell checker. The scan ran fairly quickly, and reported 76 links checked, 75 verified, 12 good, 63 bad.
The tool spotted all 4xx and 5xx errors. It missed just a handful of non-<A> HTML errors. It successfully spotted missing images within CSS.Screaming Frog
This standalone program requires Java to run. Java is a well-known security risk so the tool was not tested.
In the interest of total transparency, we disclose that these reviews, Dead Link City and Dead Link Checker are all authored by DLC Websites. We created Dead Link City due to the absence of any other way of reliably comparing link checking tools. In doing so we improved our own tool. The reviews are intended to be impartial and reflect the true nature of each tool.
We are open to revising and enhancing the benchmark site DeadLinkCity.com and invite comments, questions and suggestions in order to maintain an up-to-date, quality resource. Our email address is at the foot of the page. Thank you.