Accessible web experiences are simply non-negotiable in contemporary web development. Providing access to digital content inclusively means removing barriers so everyone, regardless of ability, can engage with the content they need. Accessibility tools can be helpful when pursuing the inclusion of others, and Axe-Core is one of the most widely used accessibility tools.
Axe-Core offers a variety of accessibility testing options, but some teams may need a more tailored approach to their internal standards, their interpretations of the WCAG, specific design guidelines, etc. Building an accessibility extension using Axe-Core with some custom rulesets allows for this increased accuracy.
This blog will provide insight into creating custom accessibility extensions and rulesets with Axe-Core and discuss how they fit into QA workflows, including real-device testing, and why they are so crucial for truly inclusive digital experiences.
Why Accessibility Matters More Than Ever
Digital accessibility allows websites and applications to be perceived, comprehended, navigated, and used by all, including individuals with disabilities. It extends beyond a compliance requirement to being a social responsibility, a legal necessity and a means to an expanded user base.
When it comes to users with visual, auditory, cognitive or physical disabilities, those inaccessible websites can create barriers. From non-compliance with screen readers to poor color contrast or color palettes across their site, unmanageable keyboard navigation, etc., there are numerous barriers that developers often overlook as part of the development process. Not only will these accessibility-related violations create a poor user experience, but they can also put your organization at risk of legal issues.
Axe-Core: The Industry Standard in Accessibility Testing
Axe-Core is developed by Deque Systems and is often called the de facto or industry standard product for testing accessibility. Axe-Core was built as a testing engine that works in conjunction with the day-to-day development or testing workflow, whether automated or manual. As an open-source tool, Axe-Core is actively maintained and constantly updated for the latest WCAG guidelines and ARIA best practices.
What really stands out for Axe-Core is the accuracy of assessments and the low false-positive rate. Axe-Core performs automated checks so you can identify and catch issues at the earliest possible stage in the development life cycle. Axe-Core can be integrated as part of your normal browser, testing libraries, CI/CD pipelines, and also custom-built accessibility extensions.
However, for some teams, the built-in rules and configurations of Axe-Core may not be enough. That’s when custom rulesets come into play.
GenAI-native test execution platforms like LambdaTest help in accessibility testing on real devices by providing a platform where testers can validate how accessible their websites or web apps are for users with disabilities, using actual devices and browsers.
Here’s how LambdaTest supports this:
- Real Device Testing: Perform accessibility tests on actual Android and iOS devices.
Screen Reader Support: Use VoiceOver and TalkBack to validate screen reader compatibility. - Keyboard Navigation Testing: Check focus indicators and tab order using real keyboard input.
- Zoom and Contrast Validation: Simulate high zoom and contrast settings for visual impairments.
- Cross-Browser Coverage: Test accessibility across multiple browser-device combinations.
Role of Custom Rule Sets in Accessibility Testing
Accessibility is not one-size-fits-all. Numerous industries, regions, and organizations may have distinctive specifications or additional internal design guidelines. While Axe-Core has more than enough rules, it might be lacking in specific scenario rulesets or specific design philosophies.
Why Custom Rulesets?
- Organizational Standards: Your organization may have its own specific UI standards, which may have a wider scope of guidelines that go beyond the default accessibility requirements.
- Legal Jurisdictions: The legislation of ADA (United States), EN 301 549 (European Union), or AODA (Canada) may have a different interpretation of WCAG.
- User Demographics: Your users may have unique requirements that call for even stricter standards for design.
- Design Consistency: Your users may have unique needs, such as cognitive impairments or visual impairments that may require even further levels of design practices.
- Early Feedback Loops: Identifying non-standard accessibility issues during development can be simplified by enforcing unique criteria for accessibility based on the company through custom rules for WebSocket traffic.
As mentioned earlier, by creating your own rulesets, you will be able to create accessibility standards that meet your business goals and user needs rather than following a generic checklist.
Understanding the Building Blocks of an Accessibility Extension
Understanding the parts of Axe-Core is important if you want to make a custom accessibility extension based on it that has custom rule sets to run accessibility checks.
Axe-Core Engine
This is the engine that drives your accessibility checks. Axe-Core contains all the logic and test features for standardized accessibility issues.
Custom Rules
These rules are definitions that you have created to check compliance for requirements that are unique to your organization. Each rule includes selectors to identify relevant elements, as well as logic that tests whether or not the elements meet your accessibility requirements.
The Browser Extension
Most of the time your custom accessibility extension will be developed as a browser plug-in (such as Chrome or Firefox). As a browser extension, it will provide a user interface for developers, QA testers, or designers to run checks on any web page.
The Reporting Layer
Once a scan is completed, your extension should produce a report of the findings. Reports can be displayed internally to your extension, downloaded as files, or remotely server aggregated and analyzed.
Continuous Integration Support
Although your extension can be manually used, which is useful, your custom rules are most beneficial when included within your CI pipeline, which checks for accessibility regressions automatically when code is deployed.
To get the most from your custom accessibility checks, consistency across environments is key. LambdaTest makes this easy with its scalable cloud testing platform, supporting tools like Axe-Core. You can run accessibility tests across 3,000+ real browsers and OS combinations, all integrated seamlessly into your CI/CD pipeline. This ensures accessibility is continuously tested and validated throughout your development workflow
Best Practices for Defining Custom Accessibility Rules
Defining custom rules is not simply a process of writing scripts—it requires an understanding of the user experience based on the possibilities of inclusion. There are some best practices to help develop effective and sustainable custom rules:
Involve Real Users
One of the best ways to verify your assumptions is to test the custom rules with users with disabilities. Accessing the experience with focused groups and user testing can conceptually highlight edge case instances that an automated tool could have never returned.
Align with Design Systems
Standardize the accessibility rules to your design system for enforcement at the component level. This allows all reusable UI components to be in compliance with your custom accessibility rules.
Prioritize High-Impact Issues
Don’t overburden your tool with too many rules. Stay focused on what truly makes a difference in user experience and reduces barriers. Watch your thoroughness against the usability of your rules.
Version Your Rules
Make sure your rules stay modular and version controlled. Accessibility standards, as well as internal needs, will evolve over time, and you should treat your rules as you would any other compelling part of software.
Test on Real Devices
One of the most overlooked aspects of accessibility testing is platform variability. A rule that works very well on desktop may not perform like you’d expect on mobile or assistive technologies, such as a screen reader. This is why real device testing is critical—it validates that your rules are valid and consistent on devices across screens, screen sizes, and OS-level accessibility capabilities.
Benefits of Building an Accessibility Extension with Custom Rulesets
It may seem like a lot of work to develop a customized extension, but the long-range payoffs are real:
Tighter Accessibility Governance
A customized extension is essentially a policy enforcer for your accessibility standards. It helps keep declarations uniform across teams especially in large organizations that use distributed developers and designers.
Faster Development Cycles
By being able to shift your accessibility checks to the left of the development pipeline, your teams may be aware of the issues and correct them before it has consequential and costly rework later down the development line.
Empowered Teams
With an intuitive extension and detailed feedback, developers and designers can learn and implement best accessibility practices themselves, with little to no specialist support.
Better Legal Compliance
Custom rulesets can help you proactively meet legal requirements that are industry or location-specific and decrease your chance of lawsuits and penalties.
Better User Experience
The user sits at the center of all this. Custom rulesets that represent real use cases for your users can improve overall usability for everyone, not just people with disabilities
Integration with Current Workflows
For true impact, your accessibility extension needs to be integrated completely into your current workflows. Some integrations you may consider include:
- CI/CD Pipelines: Run your checks automatically on each pull request or deployment.
- Design Tools: Ensure designers get feedback as early as possible in the prototyping phase.
- Bug Trackers: Log your accessibility violations automatically as issues in your bug tracker.
- Analytics dashboards: Follow our accessibility metrics over time to track progress and ROI.
Integrating accessibility into every aspect helps build a culture of inclusion across teams.
Real Device Testing: Bridging the Last Mile of Accessibility
Automated tools and customized rulesets can only reasonably capture common accessibility issues but are not a silver bullet. Accessibility is context-specific, and pages are rendered differently on different devices. Consider the following examples:
- Mobile screen readers perform differently than desktop screen readers.
- Touch interactions may differ from operating systems.
- Zoom and reflow behavior on small screens may affect how the layout is displayed.
This is why real device testing is critical—it validates if your custom rules and accessibility standards work on the devices your users actually use. Adopting this testing strategy within your customized extension will assist with end-to-end accessibility.
Common Pitfalls to Avoid
Even though you have the best of intentions, your team can accidentally slip into common pitfalls that might reduce the value of accessibility extensions:
- Overloading with Rules: Too many checks can overwhelm developers. Focus on checks that are going to have the biggest impact.
- Rigid Rule Definitions: Accessibility can have contextual dependencies. Don’t hard-code context assumptions.
- Ignoring Design Input: Developers shouldn’t build rules in a vacuum. Talk to designers and UX experts to get a sense of the benefits and drawbacks of rules.
- No Feedback Mechanism: Each violation of your rules should be followed by clear, operable feedback
- Neglecting Maintenance: As technologies and standards change, your rules should change as well.
Understanding some of the frequently encountered pitfalls will assist in making your accessibility strategy sustainable.
Conclusion
Accessibility isn’t just a check box; it is an on-going commitment to inclusion. Tools such as Axe-Core are great, but nothing beats the validation of building a custom accessibility extension with the right tailored rules making the testing process more relevant and scalable with integrations.
At the end of the day it doesn’t matter the value of these tools. If you are not considering actual device testing and user-centered design, you are not creating true accessibility.
At its essence, Accessibility is the right thing to do and provided you use the right approach, it is achievable.
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