Link Validator for TYPO3

Broken links cost rankings and trust, and most TYPO3 websites have more of them than expected

A TYPO3 website with 500 pages contains 3,000-5,000 links on average. Experience shows that 2-5% of them are broken: deleted pages, changed URLs on external websites, typos in manually entered links. That adds up to 60-250 broken links that send visitors to 404 pages and signal to Google that the website is poorly maintained. An automated link check tests internal and external links and reports problems before they affect rankings and user experience.

TYPO3 ships with its own link validator in the core (EXT:linkvalidator). dreipc_linkvalidator is published neither in the TER nor on Packagist or GitHub, so what the extension adds on top of the core cannot be verified. For websites with more than 200 pages, automated link checking is not a luxury but a must.

Typical use cases

Corporate websites with external links. Corporate websites link to partners, suppliers, industry associations, legal texts and press articles. External URLs change without warning: a link to an EU regulation works today, and next week the page has moved. The core link validator checks external links via HTTP request and reports addresses that return an error or do not respond.

Universities and educational institutions. University websites are among the most link-heavy sites of all: academic regulations, forms, course catalogs, staff directories, partner universities. On one university website with 12,000 pages, the link check found 1,400 broken links: 800 internal (deleted pages, restructured sections) and 600 external.

Editorial portals with archive content. News portals and magazines with thousands of articles link to each other and to external sources. Over the years, broken links accumulate, especially in older articles. A monthly link check identifies new problems before they pile up.

Technical architecture

The basis of every link check in TYPO3 is the core link validator. It checks links at database level: it analyzes the bodytext and header_link fields and other configured fields in the content table, identifies links to deleted pages or files and checks external URLs via HTTP request.

The check runs as a TYPO3 scheduler task, typically once a week at night. The task scans all configured tables and fields for links, distinguishes between internal links (t3://page?uid=123), file links (t3://file?uid=456) and external links (https://…), and checks every link for availability.

Internal links are checked against the TYPO3 database: does the linked page still exist? Is it visible, not deleted and not expired? For file links, the check verifies that the referenced file still exists in FAL. External links are checked with an HTTP HEAD request (faster than GET, because no body is transferred). If the HEAD request fails, a GET request follows as a fallback.

The results appear in the “Check Links” backend module as a table that can be filtered by link type (internal, external, file) and by depth in the page tree. Each entry shows the element, the page path, the link target, the error message and a pencil icon that leads straight to the editing form.

Common problems and solutions

False positives with external links. Some websites block automated requests (bot protection, Cloudflare challenge). The link works in the browser, but the link validator reports a 403 or a timeout. The fix: set a meaningful user agent header, choose a generous timeout (both via TSconfig) and exclude known false-positive domains, with a check class of your own or with brofix (see below). For one client, these adjustments cut the false-positive rate from 12% to under 2%.

Checks take too long on large websites. Checking 10,000 external links one after another takes several hours. The fix: run the check at night via the scheduler instead of the button in the module, split it into several tasks for individual sections of the page tree and adjust the check frequency (external links weekly, internal links daily; internal links can be checked quickly with a database query).

Editors ignore the reports. The most common reason for ever-growing broken link lists: nobody feels responsible. The fix: enable email notifications to the responsible editors. The core link validator itself already sends a report by email from its scheduler task, each task covering one starting point in the page tree. With one task per section, each editor receives only the broken links in “their” section.

Migration and version compatibility

TYPO3’s core link validator (EXT:linkvalidator) has been part of the core since TYPO3 4.5 and is continuously developed. In TYPO3 v12 and v13, it has improved significantly: better performance, a new backend UI and reworked scheduler integration. dreipc_linkvalidator is published neither in the TER nor on Packagist, so there is no official version for v12 and v13 there either.

For projects on TYPO3 v12/v13, the question is whether dreipc_linkvalidator is still needed. The core link validator has covered the essentials itself since TYPO3 4.5: HTTP-based checks of external links, scheduler integration, email reports and a backend view with filtering. Since v13, however, checking external links has to be switched on explicitly. What is missing is an allowlist for false positives.

The alternative: replace the core link validator’s check class for external links with your own that skips known false-positive domains, or use the brofix extension, which comes with such an exclusion list. There are also external tools (Screaming Frog, Ahrefs, Semrush) that check for broken links as part of their SEO audits, but they are not integrated into TYPO3. Gosign recommends the core link validator combined with a monthly external crawl for maximum coverage.