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Nathan Gaidai
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What is WCAG?

What is WCAG?

Table of Contents

No matter the race, nationality, culture, creed, or disability, everyone has the right to gain access to public data from the web. As the internet radically grew in the mid-1990s, an international organization called the World Wide Web Consortium (W3C) was formed. Soon after, the organization identified that most published websites had accessibility concerns.

The goal of W3C is to implement technical standards for web-based technologies worldwide. W3C creates guidelines for web developers to use as a foundation for crafting well-rounded websites. One of the most notable contributions of W3C was the release of Web Content Accessibility Guidelines, WCAG for short. This might be a bit of a long read so sit back, and have a cup of coffee or tea while we go through it chronologically.

What is WCAG and How did it Start?

In May 1999, W3C released the first version of WCAG. The guidelines contained a detailed explanation of how to make web content accessible for people with disabilities. While the primary goal was to promote accessibility, it also had an effect in terms of increasing web traffic.

Developers are attracted to follow W3C’s WCAG because it does not only help people with disabilities. By following the guidelines websites become more effective and marketable. Companies that have websites with W3C’s standards tend to attract more traffic due to the accessibility features.

About WCAG 1.0

WCAG 1.0 had fourteen guidelines that explain the general principles of accessible design. Each guideline included a number, a statement, guideline navigation links, the rationale including the target audience, and a list of checkpoint definitions.

List of Guidelines

  1. Provide alternatives to auditory or visual content
  2. Do not rely on color alone
  3. Use markup and stylesheets properly
  4. Clarify natural language usage
  5. Create tables that transform gracefully
  6. Ensure that pages featuring new technologies transform gracefully
  7. Ensure user control of time-sensitive content changes
  8. Ensure direct accessibility of embedded user interfaces
  9. Design for device independence
  10. Use Interim solutions
  11. Use W3C technologies and guidelines
  12. Provide context and orientation information
  13. Provide clear navigation mechanisms
  14. Ensure that documents are clear and simple


Each checkpoint under WCAG 1.0 has three priority levels that impact accessibility. Priorities 1, 2, and 3, give the developer a quick indication of why it is important to follow a specific checkpoint.

  • Priority 1 is a basic requirement for most websites. The author must follow this guideline. Else, one or more groups of people will find it impossible to access information.
  • Priority 2 significantly improves the accessibility of your website. The author should follow this guideline. Else, one or more groups of people will find it difficult to access information.
  • Priority 3 greatly improves the accessibility of your website. The author may implement this guideline as it becomes easier for one or more groups of people to access information.

Conformance Levels

Upon completing the guidelines and following the checklist, certain conformance levels are provided on a website. You can think of it as a grading system that marks the level of accessibility of a website. 

  • Conformance level “A” means that all priority level 1 checkpoint is satisfied.
  • Conformance level “AA” means that all priority levels 1 & 2 checkpoints are satisfied.
  • Conformance level “AAA” means that all priority levels 1, 2, and 3 checkpoints are satisfied.

WCAG 2.0 and its Layers of Guidance

Many individuals and organizations worldwide have contributed to the development of WCAG 2.0 which serves as a carefully planned upgrade to the previous version. 

In December 2008, W3C introduced this new version with wider accessibility coverage. New web accessibility guidelines were provided to web developers to help individuals challenged by the following disabilities:

  • Visual
  • Auditory
  • Physical
  • Speech
  • Cognitive
  • Language
  • Learning
  • Neurological

Unlike WCAG 1.0 which directly explains the guidelines and how it should be implemented, WCAG 2.0 has a slightly different approach. Implementation requires web developers to understand & follow unique layers of guidance in sequence.

What is wcag


This section explains the basic idea or the fundamental truth about web accessibility. Four pillars will serve as the foundations upon which developers build. Suppose any of these principles are not met. In that case, people with disabilities will not be able to understand the contents of your website:

  1. Perceivable: The end user must be able to perceive the website’s information and user interface components in a presentable manner. It should be visible to all their senses.
  2. Operable: The end user must be able to navigate and operate the web interface. It should not require any action that a user can’t perform.
  3. Understandable: The users must understand how to operate the user interface and the contents of your site. It should not have any content or operation that is beyond their understanding.
  4. Robust: Your website should be well-rounded so that it can be interpreted by assistive technologies such as text-to-speech readers, speech input software, alternative input devices, etc. 


Each principle listed above includes a total of 14 guidelines underneath them. To better understand the structure by far, think of principles as “categories” and guidelines explain basic goals to satisfy each category. Below are descriptions of guidelines under the four principles.

Perceivable Provide text alternatives
Provide alternatives to time-based media
Presentation of content should be adaptable without losing information
Content should be distinguishable enough for end users to see or hear
Operable All functions should be available on the keyboard
Provide sufficient time to read and use content
Avoid designing content in a way that is known to cause seizures
Help users navigate, find content, and determine where they are
Understandable Content should be readable and understandable
Web pages should appear and operate in a predictable way
Users must help functions to avoid or correct mistakes
Robust Website must be compatible with current and future agents as well as assistive technologies

Success Criteria

Like how guidelines are sub-sections of principles, success criteria are sub-sections of guidelines. The section includes general instructions about how guidelines should be accomplished. It serves as a checklist similar to conformance levels in WCAG 1.0. Also, WCAG 2.0 still maintains level “A,” “AA,” and “AAA” conformance definitions.

Sufficient and Advisory Techniques

At this point, people who aren’t web developers might be overwhelmed by the sheer volume of information about web content accessibility guidelines. For newer web developers, there might even be confusion about what to do and where to start.

The good news is that W3C has documented the guidelines well up until listing down techniques to allow developers to understand better how the guidelines should be addressed. In the document for WCAG 2.0, the link for How to Meet, found under guidelines will take you to a full list of documentation conveniently organized in a vertically stacked list known as an “accordion menu”.

What is WCAG 2.1 and Why do we Need it?

The updated version of WCAG as of February 2023 would be version 2.1. At this point, readers might ask: Should I still implement version 1.0? What’s the difference between 2.0 and 2.1? Let’s talk about it further.

For the first question, although it is nice to know the older version of WCAG, implementing the newest one should be the priority for time-sensitive projects. As time goes by, assistive technology becomes more advanced and web developers should cope, this is one reason why W3C continuously improves its standards.

For the second question about the difference between version 2.0 and 2.1. Principles and guidelines remain the same. However, there are 17 additional success criteria. These new criteria include new techniques designed to cater to the needs of different types of end users. 

The new features of WCAG 2.1 under the principles of perceivable, operable, and robust focused on, mobile users, and people with vision, cognitive, learning, and motor impairments.

  • 5 new success criteria at level A
  • 7 new success criteria at level AA
  • 5 new success criteria at level AAA

Future Plans for WCAG

Currently WCAG 2.2 has been drafted and is scheduled to be published on April 2023. It includes modifications and obsoletion of some success criteria.

As our generation ushers a new era of technology, new types of disabilities are introduced and new web-based applications are being developed. There are also ongoing talks and research about how to make immersive worlds such as the metaverse more accessible to a wider variety of people. People can expect that the web accessibility guidelines will be updated as we delve deeper into the digital age.

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