WCUS Accessibility Checker Showcase

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Why We Built It

“Scratching our own itch.”

• Needed a solution to issues with existing tools:
• Generic rule sets don’t know WordPress – they can result in more false positives and have lower accuracy.
• Browser extensions can only test one page at a time and don’t store a history.
• SaaS options charge per page and per scan – tens of thousands of dollars per year.
• Scanning tools external to WordPress require retroactive remediation and don’t proactively warn content creators before they hit publish.

Try Accessibility Checker

Spin up a full demo of Accessibility Checker to try out all the features for yourself.

Free vs Pro

Free on dot org:

• All accessibility checks.
• Unlimited scanning of posts and pages.
• In-post and front-end reports.

Pro features:

• Scan custom post types.
• Full site scanning and full-site reports.
• Ignore log and governance features.
• Audit history add-on (small business and above).

From Idea to MVP

• Developed during the COVID-19 lockdown.
• Evaluated existing tools and plugins; identified gaps in WordPress accessibility solutions.
• Built a prototype ruleset that scraped HTML and displayed evaluation results in the WordPress admin.
• Refined rules collaboratively for accuracy and WordPress-specific checks.
• Created comprehensive documentation for user education, onboarding, and correct rule application.
• Launched with a freemium model: a full-featured free version and a Pro version with advanced features.
• MVP launched at the end of 2020.
• Continuous refinement of rules to improve accuracy and coverage.

Technical Considerations

• Server Performance and Configuration
  • Caching and efficient queries
  • Optimized database indexing
  • Require specific PHP extensions
  • Unconventional SSL and WordPress configurations
• JavaScript Execution
  • Runs in an isolated environment with the scan app injected.
  • Requires management of cross-origin restrictions.
  • Involves handling browser memory usage.
  • Mitigates timeout issues for optimal performance.
• Custom Database Table Management
  • Improves performance with optimized indexing.
  • Ensures faster queries and better scalability.
• Notable Packages
  • WooCommerce Action Scheduler
  • PHP Simple HTML DOM Parser (Fork)
  • DaveChild / Text-Statistics (Fork)
  • Deque Axe-core
• Accessibility Standards
  • An accessibility plugin must itself be accessible!
  • Tested with VoiceOver, NVDA, and Jaws.
  • Tested by multiple blind users.

Creating the Best Rule Set for WordPress

• Initial rules were all PHP-based.
  • Pro: scans could run in the background using Action Scheduler.
  • Con: Lacks accuracy with CSS variables or JS modifications.
• Major technical challenge:
  • How to keep scanning on the server with zero cost for free users while having the most accurate results?
  • Solution: Inject our JavaScript scanner app into a fully rendered, isolated environment to scan and return detected issues.
• Curated and modified axe-core rule set optimized for WordPress users.
  • Axe-core promises you can find on average 57% of WCAG issues.
  • Extended Axe-core rules to mitigate false positives.
  • Combined Axe-core rules in single rules to minimize user confusion and reduce noise.

Examples of Rule Improvements for WP

• Don’t flag:
  • aria-hidden warnings on core spacer blocks.
  • Possible heading in block quotes.
  • Anything in the admin bar.
  • Utility plugins: Query Monitor
• Run specific checks on the_content instead of the entire page.
  • Readability
  • Missing subheadings
• Rules look for specific WordPress plugins (in contrast to SaaS that only has generic rules).

Going Enterprise

“Accessibility Checker was one of the major differentiators behind NASA selecting WordPress over other CMS platforms they evaluated.”

JJ Toothman, Lone Rock Point
Dev team lead new NASA.gov website

• WordPress VIP Compliant.
• Level Up Development Workflow
  • Refactored using Object-Oriented Programming (OOP) principles.
  • Fully adopted WordPress Coding Standards (WPCS).
  • Implemented PHPUnit, Security and integrated testing.
• Removed insecure packages and libraries to strengthen security.
• Optimized database and queries to handle over 1 million records.
• Refactored scanning algorithms for up to 7 times faster scans.
• Introduced front-end reports for non-technical content editors.
• Added WP-CLI for command-line management and automation.
• Created Audit History Add-on

2023 Gaady Award Winner

Received a 2023 Gaady award “In recognition of elevating accessibility to a first class citizen” from the Global Accessibility Awareness Day Foundation.

Has 4,000+ active installs, 5 out of 5 stars rating on WordPress.org.

What’s Next

• Making fixing problems easier:
  • Global fixes you can turn on in your settings.
  • Ability to fix/ignore problems in reports.
• Dashboard to be able to view multiple websites’ reports in one place.
• Issues specific to user roles.
• Email notifications.
• Industry benchmarking and open data reporting.