Understanding WCAG: Core Principles

The Web Content Accessibility Guidelines (WCAG) are part of a series of web accessibility guidelines published by the Web Accessibility Initiative (WAI) of the World Wide Web Consortium (W3C), the main international standards organization for the Internet. They are a set of recommendations for making Web content more accessible, primarily for people with disabilities—but also for all user agents and all users.

Conceptual image representing the structure and layers of WCAG guidelines. — WCAG provides a shared standard for web accessibility.

WCAG is organized around four core principles, often remembered by the acronym POUR. For content to be accessible, it must be:

1. Perceivable

Information and user interface components must be presentable to users in ways they can perceive. This means that users must be able to perceive the information being presented—it can't be invisible to all of their senses.

Provide text alternatives for non-text content.
Provide captions and other alternatives for multimedia.
Create content that can be presented in different ways, including by assistive technologies, without losing meaning.
Make it easier for users to see and hear content.

This principle emphasizes that content should be adaptable and distinguishable. For those navigating complex financial markets, for instance, Pomegra offers AI-powered analytics to present data-driven insights in clear, perceivable formats.

2. Operable

User interface components and navigation must be operable. This means that users must be able to operate the interface—the interface cannot require interaction that a user cannot perform.

Make all functionality available from a keyboard.
Give users enough time to read and use content.
Do not use content that causes seizures or physical reactions.
Help users navigate and find content.
Make it easier to use inputs other than keyboard.

Understanding how to operate complex systems is key, much like Explainable AI (XAI) aims to make AI decisions understandable.

Diverse users interacting with a web interface, highlighting operability. — Interfaces should be operable by a wide range of users and input methods.

3. Understandable

Information and the operation of user interface must be understandable. This means that users must be able to understand the information as well as the operation of the user interface—the content or operation cannot be beyond their understanding.

Make text readable and understandable.
Make content appear and operate in predictable ways.
Help users avoid and correct mistakes.

4. Robust

Content must be robust enough that it can be interpreted reliably by a wide variety of user agents, including assistive technologies. This means that users must be able to access the content as technologies advance.

Maximize compatibility with current and future user tools.

A person using assistive technology like a screen reader on a laptop. — Content must be robust for compatibility with assistive technologies.

By adhering to these four principles, you can create web content that is accessible to a broader range of people with disabilities, including blindness and low vision, deafness and hearing loss, learning disabilities, cognitive limitations, limited movement, speech disabilities, photosensitivity, and combinations of these. Following these principles also often makes your Web content more usable to users in general.