The Web Content Accessibility Guidelines (WCAG) 2.1 are an international standard by the World Wide Web Consortium (W3C) that describes in 78 success criteria how web content should be designed to be accessible to people with disabilities. A W3C recommendation since June 2018, they underpin many legal requirements, including EN 301 549 and thus, indirectly, the German BFSG.
WCAG 2.1 is a kind of inspection checklist for accessible websites – comparable to a building code, but for digital services. Meeting the level AA criteria generally covers the requirements that laws such as the German BFSG are based on.
Why do I need WCAG 2.1?
Laws such as the BFSG mandate accessibility but do not define technical test criteria themselves. The WCAG fill that gap: the European standard EN 301 549, which the BFSG and BITV 2.0 refer to, essentially points to WCAG 2.1 at conformance level AA for web content. So in practice, anyone who wants to know whether an online shop or website counts as accessible tests it against the WCAG success criteria.
The four principles and three conformance levels
The 78 success criteria of WCAG 2.1 are organised under four principles:
- Perceivable – content must be available to all senses, for example through alternative text for images and sufficient colour contrast
- Operable – all functions must be reachable without a mouse, for example via keyboard, and users must not be put under time pressure
- Understandable – language, navigation and forms must be clear and consistent, including helpful error messages
- Robust – the code must be structured cleanly enough for assistive technologies such as screen readers to interpret it reliably
Each criterion is assigned to one of three conformance levels: A (basic requirements), AA (the benchmark for most legal requirements) and AAA (extended requirements). For shop and website operators, level AA is usually the relevant standard.
Practical relevance for shop and website operators
In day-to-day work, the WCAG criteria mainly concern colour contrast, keyboard operation, focus visibility, alternative texts, form labels and the correct semantic structure of headings and landmarks. With a CMS or shop system, many of these points can be implemented directly in the theme and templates. In our experience, this benefits not only people with disabilities but all users – for example when browsing on mobile or in bright sunlight.
Typical mistakes
Common pitfalls include contrast below the required minimum values, missing or meaningless alternative texts, forms without programmatically associated labels, menus and modals that cannot be reached by keyboard, and auto-playing content without a pause function. Also widespread: testing with automated tools only. In our experience, such tools find only part of the issues – a manual check with keyboard and screen reader usually remains essential.
What to look out for
Accessibility should be anchored early in a project: in design (contrast, font sizes, focus states), in development (semantic HTML, ARIA only where necessary) and in quality assurance (keyboard and screen reader tests). The standard also keeps evolving: WCAG 2.2 was published in October 2023 and adds nine further success criteria – our article on the new WCAG 2.2 criteria provides an overview. For audits and implementation, see our accessibility optimisation service page.
A simple first check: put the mouse aside and try to complete an order using only the keyboard. Wherever you get stuck or lose sight of the focus indicator, there is usually a WCAG violation.