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A Guide to Accessibility in Web Development and Design

by  mangrove team
published on 03.25.2020

With an estimated 48.9 million people in the US living with a disability, it’s crucial for companies to prioritize website accessibility.

First and foremost, it’s important from a values perspective—making the web accessible to the widest range of people is simply the right thing to do. It may also be important from a legal perspective. The Web Accessibility Initiative has established guidelines intended to afford everyone equal access to online content. Companies that fail to comply with their standards risk being sued under the Americans with Disabilities Act. This article presents an overview of what this all means and what you should consider to make your site more accessible to all users.

This is part 1 of a 4-part series on web accessibility. Check out our other articles in the series:

Understanding Accessibility and Usability

We often think of web accessibility solely in terms of making it easier for users with disabilities to interact with and enjoy the web, but designing with the goal of making web content generally more usable for everyone ultimately benefits users in a wide variety of circumstances. 

Consider three different people: One was born with one arm, the second broke their arm recently in a biking accident, and the third is using one arm to hold a baby. If you’re a designer working on the UI for a new application and you recognize that not everyone will be operating the app with two hands, you’re creating a more suitable product for all your users—whether their limitations are permanent, temporary, or situational. 

Figures with One Arm, Injured Arm, Holding Baby

Where do accessibility standards come from?

How can we ensure that the web is accessible to as many people as possible? The Web Accessibility Initiative (WAI) has established a series of testable criteria referred to as Web Content Accessibility Guidelines (WCAG). The guidelines outline content, design and coding parameters that set the international accessibility standard. WCAG 2.0 defines the current standards and will not be deprecated or replaced for several years, although work has begun on WCAG 3.0.

The "POUR" Principles of Accessibility

The four main guiding principles of accessibility in WCAG 2.0 are:
(note: descriptions in this list are taken straight from, and links point to a wealth of additional information on each of the POUR principles via

  • 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)
  • 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)
  • 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)
  • 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 (as technologies and user agents evolve, the content should remain accessible)

If any of the above principles are not true, users with disabilities may not be able to use your website.

Understanding the levels of accessibility

The Web Content Accessibility Guidelines fall into three levels:

  • “A” covers the basics and provides a minimum level of conformance. These standards make a website easier to navigate with assistive technology and take into account color contrast, text sizing, and other elements that form the foundation of an accessible site.
  • “AA” addresses a wider range of accessibility challenges. This level should be the goal for most sites focused on accessibility compliance to satisfy the rules of an institution or a legal requirement. It is most often the level of accessibility that needs to be met when referenced by the W3C or in legal matters.
  • “AAA” is the highest level of conformance and requires complex updates. Websites rarely reach, nor maintain, this level in all aspects of content, design, and development.

A Certified B Corp, Mangrove is a woman-owned website design and development company with a diverse, talented team distributed around the globe. We’ve been building websites since 2009 that amplify the work of change-making organizations and increase the competitive power of businesses owned by historically marginalized people.

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