How can I properly test the ac­ces­si­bil­i­ty of a website?

There are several ways to test your website’s ac­ces­si­bil­i­ty. Depending on your goals, site com­plex­i­ty, and desired technical depth, different tools and methods can help identify, assess, and fix common ac­ces­si­bil­i­ty issues.

How can I check if my website is ac­ces­si­ble?

There are multiple ways to test a website’s ac­ces­si­bil­i­ty. Ideally, you’ll make use of a com­bi­na­tion of automated tools and manual testing methods.

To start with, you can use browser plugins or online checkers to detect obvious issues. A common first step here is testing for color contrast, al­ter­na­tive text for images, or checking the semantic HTML structure and form ac­ces­si­bil­i­ty, using the <label> tag. However, many ac­ces­si­bil­i­ty barriers go un­de­tect­ed by tools, such as unclear nav­i­ga­tion or confusing language.

Manual testing helps fill this gap by having real users or ac­ces­si­bil­i­ty experts using assistive tech­nolo­gies test the website. The results of all tests should be doc­u­ment­ed and pri­or­i­tized in order to implement gradual im­prove­ments going forward.

What is the legal framework for ac­ces­si­bil­i­ty in the U.S.?

In the United States, ac­ces­si­bil­i­ty for digital content is governed primarily by:

• The Americans with Dis­abil­i­ties Act (ADA), which has been in­creas­ing­ly in­ter­pret­ed by courts to apply to websites, es­pe­cial­ly for busi­ness­es serving the public.
• Section 508 of the Re­ha­bil­i­ta­tion Act, which applies to federal agencies and mandates that elec­tron­ic and in­for­ma­tion tech­nol­o­gy must be ac­ces­si­ble to people with dis­abil­i­ties.

Ad­di­tion­al­ly, the Web Content Ac­ces­si­bil­i­ty Guide­lines (WCAG) 2.1 serve as the de facto technical standard for achieving ac­ces­si­bil­i­ty com­pli­ance, even though they are not directly codified into law for private busi­ness­es. Non-com­pli­ance can lead to lawsuits or U.S. De­part­ment of Justice (DOJ) in­ves­ti­ga­tions, par­tic­u­lar­ly if a website creates barriers for users with dis­abil­i­ties.

Ac­ces­si­bil­i­ty testing basics using automated vs. manual tests

Before a website can be con­sid­ered ac­ces­si­ble, it needs to be tested across different usage scenarios. This requires both automated testing tools and manual testing — ideally used together. Each method has its own strengths and catches different types of ac­ces­si­bil­i­ty barriers.

Automated testing

Automated tests involve quick, efficient checks using software tools. They can detect issues like missing al­ter­na­tive text, poor color contrast, or incorrect ARIA roles. These tools are par­tic­u­lar­ly useful for initial ac­ces­si­ble web design as­sess­ments and for ongoing quality assurance. However, when testing ac­ces­si­bil­i­ty with these tools, you should keep in mind that they can only discover a certain per­cent­age of potential barriers. Key problems such as unclear language, in­ter­ac­tive func­tion­al­i­ty flaws, or unclear nav­i­ga­tion struc­tures often go unnoticed.

Manual testing

Manual testing fills the gaps left by automated testing methods through targeted usability testing and expert analysis. These manual testing pro­ce­dures include operating the entire website using a keyboard, testing com­pat­i­bil­i­ty with screen readers, and assessing how clear and un­der­stand­able the language and content are. This process actively in­cor­po­rates the per­spec­tives and ex­pe­ri­ences of users with motor, sensory, or cognitive im­pair­ments. Only through this com­ple­men­tary human eval­u­a­tion can many barriers that automated tools miss be iden­ti­fied.

If you want to determine whether your website is truly ac­ces­si­ble, im­ple­ment­ing a struc­tured testing process that combines both automated and manual methods is essential.

Top 5 website ac­ces­si­bil­i­ty checkers

For an initial overview of a website’s ac­ces­si­bil­i­ty, automated tools — also known as website ac­ces­si­bil­i­ty checkers — are par­tic­u­lar­ly suitable. Below is a selection of different options.

WAVE (Web Ac­ces­si­bil­i­ty Eval­u­a­tion Tools)

WAVE is a practical and free browser tool that allows you to quickly evaluate the ac­ces­si­bil­i­ty of in­di­vid­ual web pages. It high­lights iden­ti­fied barriers directly within the page layout, im­me­di­ate­ly showing where im­prove­ments are needed. Ad­di­tion­al­ly, WAVE offers specific guidance and rec­om­men­da­tions on how to fix the issues it finds. The tool is par­tic­u­lar­ly well-suited for beginners who want to get a quick overview of their site’s ac­ces­si­bil­i­ty. In addition to the browser extension, WAVE also offers a paid API and a test engine that allows you to automate ac­ces­si­bil­i­ty testing and integrate them into de­vel­op­ment processes.

axe DevTools (by Deque Systems)

axe DevTools is a powerful, developer-focused browser plugin that provides a free, precise, and detailed analysis of website ac­ces­si­bil­i­ty. It detects a wide range of issues based on WCAG standards and provides specific guidance for fixing them, greatly sim­pli­fy­ing the work involved. The plugin is suitable for both de­vel­op­ers and QA teams looking to test ac­ces­si­bil­i­ty ef­fi­cient­ly. Deque Systems also offers ad­di­tion­al paid solutions to test website ac­ces­si­bil­i­ty. These enable seamless in­te­gra­tion into common de­vel­op­ment en­vi­ron­ments, IDEs, and CI/CD pipelines, allowing ac­ces­si­bil­i­ty testing to be automated as part of the de­vel­op­ment workflow.

Google Light­house

Google Light­house is an in­te­grat­ed testing tool in the Chrome browser, ac­ces­si­ble directly via the Developer Tools. Among other features, it provides an Ac­ces­si­bil­i­ty Score that gives a quick overview of a website’s ac­ces­si­bil­i­ty, along with specific sug­ges­tions for im­prove­ment. Light­house tests include color contrast, semantic HTML struc­tures, and al­ter­na­tive texts for images. The tool also analyzes other aspects such as per­for­mance, search engine op­ti­miza­tion (SEO), and best practices, making it par­tic­u­lar­ly useful for com­pre­hen­sive website op­ti­miza­tion. Since it runs directly in the browser, no ad­di­tion­al in­stal­la­tion is needed, which makes getting started easier.

Siteim­prove Ac­ces­si­bil­i­ty Checker

Like the tools mentioned above, the Siteim­prove Ac­ces­si­bil­i­ty Checker is a free browser plugin that checks the ac­ces­si­bil­i­ty of web pages directly in the context of the current view. The tool visually high­lights detected issues and clas­si­fies them according to WCAG criteria, severity, and affected user groups. Par­tic­u­lar­ly helpful is the clear ex­pla­na­tion of each issue and specific sug­ges­tions for fixes, making the tool ac­ces­si­ble even to non-de­vel­op­ers. Siteim­prove em­pha­sizes practical relevance and user ori­en­ta­tion, making it ideal for content editors and users with limited technical knowledge. The tool can also be in­te­grat­ed into the paid Siteim­prove platform, allowing quality assurance, analytics and ac­ces­si­bil­i­ty to be managed centrally.

Ac­ces­si­bil­i­ty Insights

Ac­ces­si­bil­i­ty Insights is a free tool developed by Microsoft, available as a browser extension for Chrome and Edge. It supports both quick spot checks and in-depth ac­ces­si­bil­i­ty testing based on the WCAG guide­lines. The tool offers two main functions: a FastPass for quick automated checks and an As­sess­ment mode that allows for step-by-step manual testing. Par­tic­u­lar­ly helpful is the visual high­light­ing of barriers directly on the page, along with a struc­tured and well-doc­u­ment­ed guide to fixing issues. Ac­ces­si­bil­i­ty Insights is specif­i­cal­ly aimed at de­vel­op­ers and is also available as a stand­alone app for Windows.

Manual testing and ac­ces­si­bil­i­ty aids

Many problems that users encounter in everyday browsing can only be detected through manual testing. These include barriers related to content com­pre­hen­sion, structure, usability, or actual user ex­pe­ri­ence. The following methods and tools provide practical ways to test a website from different per­spec­tives.

Keyboard nav­i­ga­tion

One essential manual test is to operate the website entirely using only the keyboard. This involves checking whether all content and functions can be accessed and used without a mouse. Typically, the Tab key is used to move between elements, arrow keys for nav­i­ga­tion, and Enter or Spacebar to select items. This type of test is es­pe­cial­ly important for users with motor im­pair­ments or those who rely on keyboard-based input devices.

Screen reader tests

Screen readers are programs that convert screen content into speech or Braille output for blind or visually impaired users. Testing with common tools like NVDA (Windows) or VoiceOver (macOS) simulates this usage scenario. These tests can reveal issues with semantic structure, such as heading hierarchy, reading order, or missing labels on in­ter­ac­tive elements. Learning to use screen readers takes time but provides valuable insights into the actual usability of a website.

Zoom and contrast checks

Ac­ces­si­bil­i­ty isn’t at odds with modern web design trends — in fact, good design is ac­ces­si­ble by default. Testing at increased zoom levels (e.g., 200%) and sim­u­lat­ing color vision de­fi­cien­cies (e.g., grayscale mode) can help reveal design flaws and barriers for users with visual im­pair­ments. Common issues include poor color contrast, content getting cut off, or interface elements that don’t scale properly. Most operating systems and browsers already include built-in features for running these checks quickly and easily.

Clarity of content

Ac­ces­si­bil­i­ty is not just a technical issue. Website content must also be easy to un­der­stand. Text should be clearly struc­tured, readable, and prefer­ably written in plain language. Check whether technical terms are explained, sentences are concise, and para­graphs are logically organized. Ar­ti­fi­cial in­tel­li­gence and language models LLMs can help evaluate how un­der­stand­able your content is, or suggest simpler al­ter­na­tive wording. In­ter­ac­tive elements, such as forms or tools for scanning QR codes on a PC should also be designed for ac­ces­si­bil­i­ty and tested ac­cord­ing­ly. This benefits not only people with cognitive dis­abil­i­ties but also users with limited reading pro­fi­cien­cy or non-native English speakers.

Check­lists and WCAG criteria

The WCAG 2.1 define four key prin­ci­ples of digital ac­ces­si­bil­i­ty: per­ceiv­abil­i­ty, op­er­abil­i­ty, un­der­stand­abil­i­ty, and ro­bust­ness — often ab­bre­vi­at­ed as POUR. These prin­ci­ples form the foun­da­tion of many rec­og­nized testing pro­ce­dures and check­lists, such as the BITV test or the practical WCAG check­lists provided by or­ga­ni­za­tions like WAI or DIAS. Such struc­tured testing tools help sys­tem­at­i­cal­ly identify ac­ces­si­bil­i­ty barriers, pri­or­i­tize necessary actions, and document progress in a trans­par­ent and traceable way.

What happens after testing?

After testing, the next step is doc­u­ment­ing and analyzing the results — ideally with clear priority ratings like “critical,” “medium,” or “low.” Focus first on barriers that create major obstacles for users or have legal im­pli­ca­tions, like missing al­ter­na­tive text for images. These problems should be your top priority.

Long-term success means building ac­ces­si­bil­i­ty prin­ci­ples into your design, de­vel­op­ment, and content creation processes. Think of ac­ces­si­bil­i­ty as an ongoing re­spon­si­bil­i­ty rather than a one-time project. Here con­tin­u­ous im­prove­ment is key. It’s also a good idea to plan follow-up testing after major changes like website re­launch­es, technical updates, or new content additions to maintain the standards you’ve worked hard to achieve.

Con­clu­sion

Testing website ac­ces­si­bil­i­ty is not a one-time effort. It’s an ongoing process. By combining automated tools, manual testing methods, and well-struc­tured check­lists, you can identify and fix many ac­ces­si­bil­i­ty barriers early on, before they become major issues. Ac­ces­si­bil­i­ty goes beyond simply meeting legal re­quire­ments. Digital inclusion makes both ethical and business sense for today’s websites.

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