When improving digital accessibility, many organisations turn to automated accessibility testing as their starting point. These tools quickly scan websites, flagging common WCAG compliance issues such as missing alt text, low colour contrast, or incorrect heading structures. They provide speed, consistency, and valuable insights that help teams identify barriers early in the development process.
The challenge is that automation alone cannot guarantee a fully accessible experience. While tools are effective at detecting code-level problems, they cannot replicate how real people navigate, understand, or interact with a site. Relying solely on automation risks overlooking usability issues that can prevent disabled users from accessing content.
In this blog, you’ll discover the limitations of automated testing, the role of manual accessibility testing, and why a combined approach is essential for creating inclusive digital experiences that go beyond compliance.
What is Automated Accessibility Testing?
Automated accessibility testing is the process of using software tools to scan digital content and identify barriers that may prevent people with disabilities from using a website or application. These tools evaluate code against recognised standards, most commonly the Web Content Accessibility Guidelines (WCAG), to highlight issues such as missing alternative text, insufficient colour contrast, or incorrect heading structure.
Unlike manual reviews, which require human judgement, automated testing provides instant feedback at scale. This makes it especially useful for catching widespread errors early in the development cycle. Many teams use it as the foundation for WCAG compliance testing and staying accessible, ensuring their digital products meet minimum accessibility requirements before moving on to more in-depth manual evaluation.
What are the Disadvantages of Automated Accessibility Testing?
Automated accessibility testing offers speed and efficiency, but it is not a complete solution. These tools are excellent at detecting code-level errors, yet they cannot replicate the way real people navigate or experience a website. Important barriers often go unnoticed unless manual testing is also part of the process.
Here are the key limitations to be aware of:
1. Automation Cannot Replicate Human Interaction
Automated testing for accessibility can confirm whether a website meets certain code-based rules, but it cannot reflect how real people experience the site. Accessibility is not only about compliance; it is about usability. Investing in accessible web development ensures that user interactions, navigation flows, and design choices are tested and refined for genuine inclusivity.
For example:
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A tool might confirm that a form has labels, but it cannot verify whether those labels are meaningful or easy to understand.
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It might detect that a website has keyboard focus indicators, but it cannot judge if the tab order is logical or user-friendly.
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It won’t catch issues related to cognitive overload, such as complex layouts, unclear instructions, or distracting design choices.
2. Lack of Keyboard Navigation & Screen Reader Testing
A website can pass automated checks with 100% compliance and still be unusable for disabled users. Many tools do not fully test how people navigate or interact with content. For example:
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A user may be unable to move through menus, buttons, or interactive elements using only a keyboard, even though the site appears compliant.
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Screen reader users rely on meaningful announcements, but automated tools cannot verify whether custom elements provide accurate spoken feedback.
These are issues that only manual accessibility testing can uncover reliably.
3. False Positives & False Negatives
Automated systems are powerful but not perfect, and their results need careful interpretation. They sometimes:
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Flag issues that are not actually accessibility barriers (false positives), leading developers to waste time fixing non-problems.
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Miss real accessibility issues (false negatives), particularly with complex interactions, dynamic content, or third-party integrations.
The gap between automated reports and real usability is one of the main drawbacks when comparing manual testing vs automated approaches. Ongoing website accessibility monitoring can help teams catch missed issues earlier and ensure fixes remain effective.
4. Automated Testing Cannot Judge Content
Automated tools can check whether certain elements exist, such as alt text or links, but they cannot determine whether those elements are useful or meaningful. For example, they cannot:
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Decide if alt text accurately describes an image.
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Evaluate whether link text like “Click here” provides enough context.
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Judge whether error messages give clear instructions.
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Assess readability, plain language usage, or logical content structure.
These content-focused checks require human insight, which is why automation should always be paired with WCAG compliance testing carried out by skilled reviewers.
Compliance vs. Usability: The 99% Myth
Some organisations believe that if their website is “99% compliant” with WCAG, they have achieved accessibility. In reality, even a single failure can create barriers that exclude disabled users. WCAG compliance testing is valuable, but passing automated checks does not always guarantee that a site is usable.
For example:
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If a “Submit” button on a payment form is not keyboard accessible, it could block disabled users from completing a purchase.
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If an essential login feature does not work with a screen reader, it could prevent users from accessing their accounts.
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If an urgent error message is not announced properly, users may not even realise an issue exists.
A website may appear almost fully compliant yet remain completely unusable for certain users. True accessibility goes beyond technical compliance and requires testing with real people. Our inclusive user testing guide explains how to gather feedback from disabled users to ensure that every interaction is functional and inclusive.
The Role of Manual Accessibility Testing
While automated checks provide speed and consistency, they cannot replace the insight gained from manual accessibility testing. Human evaluation is essential for uncovering issues that tools cannot detect and for validating whether a website is genuinely usable for people with disabilities.
Manual testing can involve:
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Keyboard testing: Ensuring users can navigate through menus, buttons, and interactive elements without relying on a mouse.
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Screen reader testing: Verifying that content is announced correctly and in a logical order.
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User testing with disabled individuals: Gathering real-world feedback from people who depend on assistive technologies to interact with digital content.
Each of these methods addresses barriers that automated accessibility testing alone will miss. Providing role-based accessibility training ensures that teams know how to apply these techniques consistently, building a stronger process that moves beyond compliance to deliver genuinely inclusive experiences.
Manual Testing vs. Automated Testing
Automation offers speed and scale, but accessibility cannot be fully measured by tools alone. The most effective approach is a combination of both methods. Manual testing vs automated testing is not a question of choosing one over the other but of understanding how they complement each other.
Automated testing quickly identifies common code-level issues, while manual testing uncovers usability barriers that only human judgement can detect. Together, they create a more reliable and inclusive testing process. Incorporating design system assessments ensures accessibility is considered consistently across both approaches.
To create truly accessible digital experiences, automated checks should be complemented with:
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Manual keyboard testing: Ensuring users can navigate without a mouse.
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Screen reader testing: Verifying that users receive the correct information through assistive technology.
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User testing with disabled individuals: Getting real-world feedback from people who rely on accessibility features.
Conclusion
Automated accessibility testing provides an efficient starting point, but it cannot deliver complete accessibility on its own. A website may achieve perfect scores in automated reports and still present barriers such as keyboard traps, missing screen reader announcements, or poor usability. These critical issues highlight the limits of relying solely on automation.
Organisations that prioritise accessibility must go further by combining automated checks with manual accessibility testing, usability reviews, and feedback from disabled users. True accessibility is not just about passing compliance checks; it is about creating inclusive digital experiences that everyone can use with confidence.
Ready to take the next step? Learn how to be accessibility compliant and build digital platforms that are both inclusive and legally robust.