Methodology
VertaaUX combines deterministic rule engines, heuristic models grounded in WCAG 2.2 and Nielsen's usability heuristics, and AI-assisted analysis to produce actionable audit reports. This page explains exactly how.
Every VertaaUX audit follows the same six-step pipeline from URL submission to interactive report.
User submits a URL. No browser extension or code snippet required. The engine accepts any publicly accessible web address and queues it for immediate processing.
A Playwright-based headless browser loads the page at 1920×1080, executes JavaScript, and waits for network idle. Timeout: 30 seconds. This ensures audits reflect what real users see after dynamic content loads.
Full DOM snapshot, computed styles, ARIA tree, and viewport screenshot are captured. The ARIA tree extraction enables accessibility analysis without relying solely on source HTML.
Five audit modules run simultaneously: Usability, Clarity, Information Architecture, Accessibility, and Conversion. Parallel execution keeps total audit time under 30 seconds regardless of page complexity.
An LLM layer reviews borderline findings, adds context-dependent analysis, and generates human-readable explanations. The LLM does not replace deterministic checks — it supplements them for nuanced, qualitative findings.
Scores, issues (with severity, WCAG reference, CSS selector, confidence, and fix guidance), and an executive summary are assembled into an interactive report. Each finding links directly to the relevant standard.
Each audit evaluates five dimensions. Every model is grounded in established standards and research.
Standards
Nielsen's 10 usability heuristics, Google's Core Web Vitals
Checks
Load time, touch target size (44×44px per WCAG 2.5.8), viewport configuration, font sizes, interactive element spacing
Standards
AI Clarity Model, reading ease metrics
Checks
Reading ease, message hierarchy, brand clarity, ambiguity detection, CTA action strength
Standards
Information architecture patterns
Checks
Link clusters, heading hierarchy, click depth, navigation redundancy, breadcrumb clarity
Standards
WCAG 2.2 Level AA
Checks
Color contrast (WCAG 1.4.3), alt text (1.1.1), form labels (3.3.2), keyboard navigation (2.1.1), ARIA landmarks, focus management
Standards
Conversion funnel heuristics
Checks
CTA placement and wording, page dead-ends, trust indicators, social proof, friction points
Each dimension starts at 100 and deducts points based on issue severity: critical issues deduct 15 points, warnings deduct 8 points, and informational findings deduct 3 points. The composite score is the weighted average across all five dimensions.
Deduction Scale
−15 points
Blocking issues that significantly harm usability, accessibility compliance, or conversion.
−8 points
Moderate issues that degrade experience or create unnecessary friction.
−3 points
Low-impact findings and optimisation opportunities for incremental improvement.
Direct answers to common questions about how VertaaUX audits are conducted and validated.
VertaaUX grounds every audit in WCAG 2.2 Level AA for accessibility, Nielsen's 10 usability heuristics for interaction quality, and Google's Core Web Vitals for performance. The WebAIM Million report found that 96.3% of home pages had detectable WCAG failures — VertaaUX checks the same criteria automatically on demand.
VertaaUX separates deterministic rule checks — which produce binary pass/fail results with no ambiguity — from LLM-assisted findings, which carry explicit confidence scores. Findings below 70% confidence are labelled as informational and never promoted to critical severity. Deque research estimates automated tools detect 30–50% of real-world issues, so VertaaUX combines automated rules with AI synthesis to maximise coverage while minimising noise.
The VertaaUX ruleset is reviewed quarterly. Updates include new WCAG criteria as they reach Candidate Recommendation status, revised Nielsen heuristic weightings based on benchmark validation, and corrections informed by continuous precision and recall tracking. The current ruleset version and changelog are published on the benchmarks page.
Yes. The sample report page shows a representative VertaaUX audit with real scores across all five dimensions, annotated issues with WCAG references and CSS selectors, severity deductions, and fix guidance. You can also run a live audit on any public URL from the homepage — no account required for the first report.
VertaaUX publishes its accuracy metrics, benchmark results, and sample outputs so you can evaluate methodology claims independently.