This translation has not been editorially reviewed yet. The German version is authoritative. German version →
Where our audit rules come from
An audit report is only as good as its sources. That is why every one of our findings states what it is based on, and why this page says who is behind those addresses. The most important distinction is the one between standard and tool: The standard is binding. The documentation of an audit program only explains how that program checks the standard.
In short: who is actually measuring here?
We measure the accessibility of your pages with axe-core, the most widely used automated WCAG checker. It comes from Deque Systems and is also built into the developer tools of Chrome, among others. What axe finds, we recalculate against the complete WCAG catalogue and add our own measurements: contrast, keyboard operation, focus. What a machine cannot decide remains open and is judged by a person; it counts neither as met nor as an open finding.
The sources in detail
W3CStandard
The World Wide Web Consortium is the international body that sets the standards of the web, among them HTML and the accessibility guidelines WCAG.
This is where the binding wording of the success criterion that was checked stands. It is the standard itself, not its interpretation.
Open w3.org ↗ · also www.w3.org
schema.orgStandard
Joint vocabulary of Google, Microsoft, Yahoo and Yandex for structured data, the machine-readable statements from which search engines and AI systems draw facts about your page.
Defines what the structured data must look like that we rate in the audit area AI visibility.
Amtliche RechtsquelleStandard
Official publication of the legal text (Official Journal of the EU or the Austrian federal legal information system).
The original text of the law: it is authoritative, not our summary.
Open eur-lex.europa.eu ↗ · also ris.bka.gv.at
Deque UniversityTool documentation
Deque Systems is a US company for digital accessibility. It develops axe-core, the audit program we use to measure your pages for accessibility. The same audit library is built into the developer tools of Chrome and into Microsoft Accessibility Insights, among others; it is the most widely used automated checker for WCAG.
Deque University is the documentation of this audit program. For every rule that was triggered on your site, it explains in detail what is behind it and how to fix it. ⚠ It is not a standard: the WCAG is binding (see w3.org); the Deque page only explains how our measuring tool checks it.
Open dequeuniversity.com ↗ · also deque.com, accessibility.deque.com
Google Web-DokumentationVendor statement
Google publishes here the requirements by which its own search and the Chrome browser rate websites, among them the thresholds of the Core Web Vitals.
The loading-time thresholds in this report (2.5 s for the largest element, 0.1 for shifting content) come from there. We did not choose them ourselves.
Open web.dev ↗ · also developers.google.com, developer.chrome.com
MDNReference work
The reference work of the Mozilla Foundation (Firefox) for web technology, the reference most frequently used by developers.
Explains the affected HTML or CSS feature neutrally and independent of any vendor.
What we measure ourselves
Much of a report we measure ourselves. Our own measurements include: recalculating every colour contrast on the rendered image instead of the source code, checking whether declining the cookie banner actually takes effect, matching the sitemap against the pages that can really be reached, and the questions no single page can answer: duplicate page titles, duplicate main headings, pages that no other page links to.
The same principle applies to every finding: An empty check is an error, not a free pass. Where nothing could be measured, that is what it says, not a tick.
