Web Content Accessibility Guidelines

The Web Content Accessibility Guidelines (WCAG) are a set of technical standards defined by the World Wide Web Congress.

The goal of WCAG, first written in 1999, is to make the Internet a more inclusive and accessible place for people with disabilities, according with the new technologies:

Following these guidelines will make the contents accessible to a broader number of people with disabilities, including blindness and low vision, deafness and hearing loss, motor limitations, language disabilities, photosensitivity, and combinations of these. It will partially improve accessibility even for those with learning disorders or cognitive limitations.

Over time, WCAGs has become an industry standard for accessibility testing, forming the basis for most Web accessibility standards and guidelines worldwide, including the European Union’s Web Accessibility Directive and AGID guidelines in Italy.

Web Accessibility Initiative (WAI)

WCAGs are written by the Web Accessibility Initiative (WAI), an initiative of the World Wide Web Consortium (W3C).

The W3C is the international consortium of IT companies that develops recommendations and sets standards for the Web, including coding languages, communication protocols, and compliance levels.

The Web Accessibility Initiative is one of the four areas of work of the W3C and, as the name suggests, ensures that anyone can take advantage of the potential of the Web regardless of disability and special needs. WCAGs are developed and regularly updated in collaboration with individuals and organizations worldwide and designed for a wide range of present and future applications.

WCAG 2.1: Principles and Guidelines

The WCAG guidelines have now reached version 2.1, published as a W3C Recommendation in June 2018. As of version 2.0, the full text of these guidelines is divided into four principles, understood as the necessary basis for access to and use of the Internet.

To be considered accessible, a website, understood as a set of information and user interface components, must be:


Content must be presented to users in ways they can perceive it, regardless of inhibiting one or more senses or motor skills.
This includes:

  • Providing text alternatives for non-text content;
  • Provide options for timed media;
  • Provide the option to represent content with simplified layouts without losing information or structure;
  • Separate the contents from the background at the level of color and hierarchy;


Interfaces must be operable, even through alternative tools or browsers.
This includes:

  • Making features available via keyboard;
  • Provide users with sufficient time to read and use the content;
  • Avoid causing seizures or other reactions, for example, with flashing contents;
  • Provide alternative navigation features;
  • Facilitate navigation with inputs other than the keyboard;


Websites must be understandable to everyone in their content and operation.
This includes:

  • Making the text readable and understandable in the lexicon and different languages;
  • Make predictable the appearance and function of Web pages
  • Help users avoid errors and facilitate them in their correction;
  • Provide contextual assistance in the actions to be carried out;
  • Make data entry actions reversible.


Content must be reliably interpreted by many user agents, including assistive technologies.
This includes:

  • Ensuring maximum compatibility in the content and markup language used.

WCAG 2.1: the three levels of compliance

Website compliance with WCAGs is divided into three levels of compliance:

A – low accessibility level
AA – medium accessibility level
AAA – high accessibility level

Layering refers to a single Web page, defined as a single HTML document available under a given URL.

All Web page sections must be compliant for it to be considered compliant. Similarly, the compliance rule will extend to the entire path if the page is located within a user path that allows you to reach a specific action.
Most state-level Web accessibility guidelines align with the AA level of WCAG 2.0 or 2.1.

Easy Checks

For a first check of the accessibility of a Web page, the Web Accessibility Initiative provides a list divided into practical points, which allows you to get an immediate idea.

  • Title of the page
  • Alternatives to image text (“alt text”)
  • Text:
    • Contrast Ratio Titles
    • (“Color Contrast”)
    • Text Resizing
  • Interaction:
    • Keyboard access and visual focus
    • Forms, labels, and errors (including search fields)
  • General:
    • Content in motion, flashing, or intermittent
    • Multimedia alternatives (video, audio)
    • Control of the basic structure

These criteria, which can be consulted in full on the dedicated page, do not constitute a conformity assessment at the regulatory level but form a helpful starting point for web professionals.

Sources and legislation


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