As soon as you start exploring accessibility, you will come across an acronym that might seem confusing at first: WCAG. If this has happened to you and you still haven't figured it out, don't worry. The goal of this guide is to provide a simple and understandable overview of the WCAG, explaining what they are, why they are important, and how they can be implemented to make websites more accessible to everyone.


Specifically, in this guide, we will cover:


What Are WCAG and Why Are They Important?

WCAG (short for Web Content Accessibility Guidelines) are a set of international guidelines developed by the W3C (World Wide Web Consortium), the organization responsible for defining global web standards, in collaboration with individuals and organizations worldwide. The goal of WCAG is to provide a shared standard for web content accessibility, helping developers, designers, and website owners make their content accessible to people with disabilities.


As stated in the introductory excerpt of the latest WCAG 2.2, following these guidelines allows content to be accessible "to a broader range of people with disabilities, including blindness and low vision, deafness and hearing loss, limited mobility, speech disabilities, photosensitivity, as well as combinations of these, and will also improve accessibility for individuals with learning disabilities and/or cognitive limitations". But that's not all: these guidelines also make web content more usable "for older individuals experiencing age-related changes in abilities and often enhance the overall usability for all users".


WCAG cover a wide range of aspects related to creating web content, including navigation, readability, site interaction, and media accessibility (images, videos, interactive content). As we will see, they are organized according to 4 fundamental principles from which the guidelines are derived. Each guideline is accompanied by verifiable success criteria and different conformance levels.


In summary, WCAG are essential to ensuring a web that is accessible and inclusive for everyone, regardless of their physical, cognitive, or technical abilities. By adopting these guidelines, websites can:

  • Increase inclusivity: make the web accessible to people with disabilities, including those with visual, auditory, motor, and cognitive impairments.
  • Enhance user experience: an accessible website is also more usable and easier to navigate, benefiting all users.
  • Meet legal requirements: in many countries, WCAG compliance is a legal requirement for public and private websites and is often part of regulations related to the rights of people with disabilities.
  • Improve SEO: many accessibility best practices, such as using alternative text for images and maintaining a clear structure, also boost search engine rankings.


A Brief History of WCAG: From WCAG 1.0 to WCAG 2.2

The Web Content Accessibility Guidelines (WCAG) were created to address the need to make the web a more inclusive and accessible place for everyone.


The first version, WCAG 1.0, was published in 1999 and consisted of 14 guidelines organized into three priority levels. The goal was to improve accessibility through recommendations tailored to the technologies of that time, such as using alternative text for images and creating alternative navigation methods. However, its strong dependence on HTML and the rapid evolution of the web soon made this version less flexible.


In 2008, WCAG 2.0 was released, introducing a major overhaul of the guidelines by establishing four fundamental principles: Perceivable, Operable, Understandable, and Robust. This change allowed for more general guidelines that could be applied to a wide range of current and future technologies, ensuring greater compatibility and adaptability. WCAG 2.0 retained the three conformance levels (A, AA, and AAA) but made success criteria more detailed and measurable, facilitating the implementation of accessibility recommendations.


Ten years later, in 2018, WCAG 2.1 expanded the scope further by introducing new criteria to enhance accessibility for "users with cognitive and learning disabilities, users with vision impairments, and users with disabilities using mobile devices."


The most recent version, WCAG 2.2, was officially published in November 2022 and introduced specific criteria to improve the accessibility of interactive content and web applications, with a particular focus on users with cognitive disabilities and older adults. WCAG 2.2 maintains the conformance level structure (A, AA, AAA) and remains backward-compatible with previous versions (WCAG 2.0 and 2.1).


WCAG 2.2 represents a crucial update but is not the final step: the web accessibility working group is already developing a new version of the guidelines, aimed at being a more extensive restructuring compared to minor updates.


The Impact of WCAG on Laws and Organizations

WCAG has had a profound impact on national and international regulations concerning digital accessibility, directly influencing the creation of laws and policies aimed at ensuring web inclusion. Many countries have adopted WCAG as an official reference for defining accessibility standards for public and private websites, effectively turning the guidelines into legal requirements.


At the European level, the Directive 2016/2102/EU on Accessibility of public sector websites and mobile applications has made compliance with WCAG 2.1 at least at level AA mandatory for all public administrations. Complementing this, the European Accessibility Act (EAA), effective from June 2025, will impose accessibility requirements on e-commerce websites, online banking services, digital platforms, and mobile applications of private companies. Similar regulations exist in other regions, such as the Americans with Disabilities Act (ADA) in the United States, the Accessibility for Ontarians with Disabilities Act (AODA) in Canada, the Disability Discrimination Act (DDA) in Australia, and the Disability Protection Act in South Korea. In all these cases, WCAG adoption is considered essential to ensure equal rights for individuals with disabilities.


For organizations, this means that non-compliance with WCAG can result in significant legal consequences, such as administrative fines, lawsuits, and reputational damage. Companies that ignore accessibility regulations risk not only being excluded from regulated markets but also losing customer trust and credibility.


Remember: even if a company does not have offices in a specific country but operates there, it is required to comply with the applicable accessibility legislation of that country.


The 4 Fundamental Principles of WCAG

Now that we have explained what WCAG is, how it has evolved, and why these guidelines are important, let's take a closer look at how they work.


As we have seen, while WCAG 1.0 focused on the more technical aspects of coding, version 2.0 introduced a different approach by establishing four fundamental accessibility principles centered around the user:


Each of these four principles, known by the acronym POUR, represents a crucial dimension of accessibility and includes guidelines that help improve content usability for all users, particularly those with disabilities. Let's examine them in detail.


1. Perceivable

“Information and user interface components must be presented to users in ways they can perceive.”


This principle concerns the ability of users to perceive content through at least one of their senses, regardless of any physical or sensory limitations.


Let's take an example to better understand: users with full vision can read text, view images, recognize visual cues in page layouts, interpret the symbolic meaning of colors, and so on. However, for blind or visually impaired users, this is not possible. For these users, information must be presented in a format they can perceive more easily, such as audio.


Under this first principle, there are guidelines requiring that content does not rely on a single type of sensory perception. These include recommendations for providing alternative text for images, subtitles for videos, or transcripts for audio content.


2. Operable

“User interface components and navigation must be operable.”


This principle concerns the ability of users to interact with a website or application using various input methods, such as keyboards, mice, touchscreens, or voice commands.


People must be able to use a website regardless of the method they choose. For example, many people navigate the web using a keyboard instead of a mouse, and if a website does not allow keyboard navigation, it will not be accessible to them.


This principle includes guidelines such as ensuring keyboard accessibility, providing alternatives to complex gestures, and avoiding content that may cause seizures or physical reactions.

 

3. Understandable

“Information and the operation of the user interface must be understandable.”


This principle refers to the user's ability to understand both the content and the ways to interact with it. The website must provide clear and consistent information so that users do not have to guess how different sections or interfaces work.


Examples of applying this principle include guidelines that require using simple language, providing clear error messages, and maintaining a predictable interface behavior. For instance, ensuring that a menu or navigation bar remains consistent across all pages.


4. Robust

“Content must be robust enough to be reliably interpreted by a wide variety of user agents, including assistive technologies.”


This principle concerns the compatibility of content with different technologies and devices, including assistive technologies. Content must be written in a way that ensures correct interpretation even with future tools and software updates.


In general, content is considered "robust" if it uses semantic code that complies with HTML and CSS standards, avoids proprietary features that only work on specific devices or browsers, and ensures that multimedia content has accessible alternatives for devices with different configurations.


The 3 WCAG Compliance Levels

In addition to being structured according to the 4 fundamental principles we have just seen, all WCAG guidelines include “success criteria”, which define what must be achieved to meet the standard. These success criteria are written as testable statements with two possible outcomes: “Compliant” or “Not compliant.”


The success criteria are classified into three levels of compliance, representing different degrees of accessibility. These levels indicate the extent and depth of measures adopted to make a website accessible. Each level has a specific objective, from addressing critical barriers to optimizing the experience for all user categories.

  • Level A: Minimum Compliance - Represents the basic accessibility requirement. It focuses on removing the most critical barriers that prevent users with disabilities from accessing content. However, it does not guarantee a fully accessible experience.
  • Level AA: Intermediate Compliance - This is the reference standard for most international regulations, such as the European Accessibility Act. It aims to eliminate most significant barriers for users, providing a more inclusive experience.
  • Level AAA: Advanced Compliance - The highest level of compliance, incorporating all criteria from Levels A and AA, along with additional requirements to ensure superior accessibility. This level is harder to achieve and is not always required by law.


Naturally, each level includes all the success criteria of the previous level. In other words, to comply with WCAG Level AA, all Level A requirements must also be met.


What Websites Must Do to Be WCAG Compliant

The best way to use WCAG guidelines is to first understand their logic and intent, and then consistently apply them during both the design and content development phases.


Contrary to what one might think, it is not just about following a set of rules, but about recognizing that the real starting point is people. The web is now an integral part of everyday life, and for people with disabilities, it can be a powerful tool to enhance their ability to independently access information, communication, entertainment, commerce, and more. Only by considering their needs can we design and develop a web that fulfills these promises instead of becoming yet another barrier.


On this journey, WCAG guidelines can guide us in making the right choices and implementing the necessary measures to ensure that our content is truly accessible to the widest possible audience.


How to Verify WCAG Compliance

As we have already mentioned, the best approach is to understand the needs of the people you are addressing and to design your content with a clear understanding of not only what they are but also the intent of the WCAG guidelines. This is the only way to ensure choices that lead to truly accessible content.


But if you already have a website, how can you verify its compliance with the WCAG guidelines?

Accessibility experts recommend an approach that combines two techniques:

  • Automated Audits: These are evaluations performed using tools or platforms that check website accessibility. These tools analyze the code and identify issues such as missing alt text, inconsistent headings, or insufficient contrast. They are usually quick and efficient in detecting obvious technical errors and allow for fast scanning of large volumes of pages, providing reports with explanations of issues and recommendations for solutions.
    Many free and paid web accessibility testing tools are available; some of the most well-known include:
  • Manual Testing: These tests are performed by qualified accessibility experts. Ideally, they should be conducted by people with disabilities or those with significant experience using assistive technologies.


Automated audits are quick and cost-effective but cannot interpret context or assess user experience. For example, they can detect whether images have alternative text but cannot determine if the text is truly meaningful. On the other hand, manual testing allows for the evaluation of aspects that automated audits cannot capture but requires time and specific expertise. This is why combining both techniques is the best way to thoroughly test content while keeping costs under control.


But which version of the WCAG guidelines should you comply with? The W3C recommends testing content based on the latest official recommendations, meaning the current version is WCAG 2.2. However, it's important to note that each version of WCAG 2 is backward-compatible. This means that WCAG 2.2 includes all the success criteria from WCAG 2.1.


Therefore, if automated audits and/or manual tests confirm that your website meets the success criteria for WCAG 2.2 at levels A and AA, you can consider it accessible to most users.


In any case, remember that accessibility testing should be conducted regularly. Being transparent about your accessibility journey is always a good practice. For example, you can publish an accessibility statement outlining the steps taken and long-term goals (in some cases, this is a legal requirement), and you can request feedback directly from your users.