WCAG
The W3C Web Content Accessibility Guidelines. They are not a law: they are the technical reference we measure against.
About the rule
- Type
- W3C technical recommendation
- Version
- WCAG 2.2, 5 October 2023 (text updated on 12 December 2024)
- Body
- World Wide Web Consortium (W3C)
- Structure
- Four principles, success criteria and three conformance levels
- Official source
- W3C, Web Content Accessibility Guidelines (WCAG) 2.2
What it says, in broad terms
WCAG gathers testable criteria for making web content accessible. Each success criterion belongs to one of the four principles and to a conformance level.
WCAG 2.2 includes the criteria of version 2.1 and adds others. Other rules build on WCAG, but each one sets its own version and level.
The four principles of web accessibility
WCAG, the technical reference we measure against, groups its criteria into four principles.
Perceivable
Visitors can perceive the information by sight, hearing or touch. For example, alternative text on product photos or enough contrast on buttons.
Operable
Everything can be used with a keyboard and without unfair time limits, and controls are big enough to press.
Understandable
Text reads well, the site behaves as expected and form errors say what happened and how to fix it.
Robust
The code is interpreted correctly by different browsers and by assistive technologies such as screen readers.
Conformance levels
Each criterion belongs to a level. A level includes the criteria of the one before.
Level A
The minimum. It covers barriers that fully block some people, such as an image with no alternative text or a function that can't be used with a keyboard.
Level AA
The one we measure. It adds, for example, the 4.5:1 contrast for normal text (criterion 1.4.3). It is the level European rules usually cite.
Level AAA
The most demanding, for example a 7:1 contrast (criterion 1.4.6). The W3C notes it can't always be applied to all content, and that is why we don't measure it.
What we measure
- Text contrast: 4.5:1 for normal text and 3:1 for large text (criterion 1.4.3, level AA). Method: an automatic check in the browser, with the measured value next to its threshold.
- Alternative text, form labels, keyboard and structure. Method: an automatic check. It covers only part of the criteria.
- In the diagnosis with human review, a person tests with a keyboard and a screen reader following the W3C's WCAG-EM method.
What we don't measure
- All the criteria of WCAG 2.2: an automatic tool detects only part of them.
- Level AAA.
- Whether a specific rule requires WCAG from you, and in which version or level.
Pending review by an adviser or lawyer
We could not confirm this against the official source, or it depends on your case. Don't take it as valid until someone has reviewed it.
- Which WCAG version and level each rule that may affect you asks for.
Open the official source. Page written on 1 November 2026.
Other rules you may have heard of
Each one answers a different question. The pages complement each other.
Law 11/2023
The Spanish law that transposes the European directive on the accessibility of products and services. Here is what it says in broad terms and what we can measure on an online shop.
See the page
RD 1112/2018
The Spanish royal decree on the accessibility of public sector websites and mobile apps. It is the rule most often mixed up with the ones for online shops.
See the page
ADA
The Americans with Disabilities Act is a United States law. It only matters to you if you sell or provide a service there, and it is a subject for a lawyer.
See the page
EAA
The European Accessibility Act is Directive (EU) 2019/882. It is the European rule that affects people who sell online the most.
See the page
EN 301 549
The European standard for the accessibility requirements of ICT products and services. It is technical and voluntary on its own, but other rules take it as a reference.
See the page
Start by measuring your shop.
The automatic audit measures what can be measured from the outside and tells you what is left for your adviser or lawyer.