Automated WCAG Scanner

An automated WCAG scanner is a tool that programmatically evaluates web pages against the Web Content Accessibility Guidelines without requiring a human tester. The scanner loads your page in a browser (or headless browser), analyzes the rendered DOM, and checks it against a rule set derived from WCAG success criteria. Modern scanners like CompliScan go beyond basic HTML parsing — they render the page with full JavaScript execution, compute actual CSS styles (including inherited and dynamic styles), and evaluate the page as a real user would experience it. This is critical because many accessibility issues only appear in the rendered state: dynamically injected content, JavaScript-driven widgets, CSS-computed contrast values, and single-page application routing.

CompliScan's automated scanner follows a precise sequence for each URL:

1. Browser launch: A Chromium instance is launched via Playwright, providing a real rendering engine identical to what users see in Chrome or Edge
2. Page load: The URL is loaded with full JavaScript execution. The scanner waits for network idle and DOM stability to ensure dynamic content has rendered
3. DOM analysis: The axe-core accessibility engine is injected into the page. axe-core is the industry-standard open-source library maintained by Deque Systems, used by Microsoft, Google, and the US government
4. Rule evaluation: axe-core runs its rule set against every DOM element. Rules check ARIA validity, color contrast computation, heading structure, form label association, keyboard accessibility, and dozens more criteria
5. Result classification: Each violation is categorized by impact (critical, serious, moderate, minor) and mapped to its specific WCAG success criterion
6. AI enrichment: CompliScan passes each violation through Claude to generate a specific fix suggestion with actual code changes

Automated WCAG scanners are powerful but not omniscient. Understanding their boundaries helps you use them effectively:

• Strengths: Speed (seconds vs. hours), consistency (same rules every time), scalability (scan hundreds of pages), and cost-effectiveness (fraction of manual testing cost). Automated scanners catch the most common violations: contrast failures (81% of sites), missing alt text (54%), empty links (49%), missing form labels (45%), and missing document language (18%)
• Limitations: Automated tools detect approximately 30-40% of WCAG 2.1 AA issues. They cannot evaluate subjective criteria: Is the alt text meaningful? Is the tab order logical? Are error messages helpful? Is the content structure cognitively accessible? These require human judgment
• False positives: Automated scanners occasionally flag issues that are not actual violations (e.g., decorative images correctly using alt="" may be flagged). CompliScan minimizes false positives by using axe-core's battle-tested rule set, which has been refined over years of real-world use

The bottom line: automated scanning is the essential first step in any accessibility program, catching the high-volume, high-impact issues that affect the most users.

CompliScan is designed for developers and teams who want to catch accessibility issues early and continuously:

• Free scan: Enter any URL and get instant results — no account required. Full axe-core analysis with AI fix suggestions for every violation
• Shield ($49/mo): Monitor 3 sites with weekly automated scans. Get notified when new violations appear after deployments or content changes
• Shield Pro ($149/mo): 10 sites with daily scans. PDF compliance reports and historical trend tracking to demonstrate remediation progress
• Agency ($299/mo): 50 sites with priority scanning and white-label reports — built for agencies managing accessibility across multiple client properties

All plans use the same scanning engine: Playwright + axe-core + Claude AI. The difference is scale, frequency, and reporting. Every scan produces the same depth of analysis — no feature gating on the scan quality itself.