Calculate WCAG 2.1 relative luminance and evaluate AA/AAA accessibility compliance.
Dual-engine contrast auditing (WCAG 2.1 & APCA), real-time typography simulation, 1-click color auto-fix, and colorblind vision preview.
Relative luminance contrast based on ISO/IEC 17025 standard calibration formulas.
APCA models human spatial perception, accounting for text size, font weight, and polarity adaptation.
Calculates and shifts lightness along the HSL color vector to the nearest compliant threshold.
The quick brown fox jumps over the lazy dog. Legible typographic scale ensures clarity across content hierarchies, regardless of device display specs.
Bold visual statements require minimum 3.0:1 contrast for universal readability.
Simulates retinal cone deficiencies to guarantee readability across all color vision spectra.
Direct execution in browser memory with full vector precision.
Select your source file from your local disk or drag and drop it into the workspace canvas.
Review automated results and use interactive controls like brush, crop handles, or sliders for precision adjustment.
Export your high-resolution file directly to local disk with full resolution integrity.
Files are processed ephemerally inside client-side RAM or temporary stateless workers. No storage, no logs.
Optimized canvas transformations and vector operations execute directly on the client thread without network transit.
Takes full advantage of modern GPU WebGL and HTML5 Canvas pipelines for fluid 60fps brush and pan interactions.
Everything you need to know about WCAG Contrast & Palette Checker
Extract distraction-free reading views from cluttered, ad-heavy web pages.
Format, validate, beautify, and inspect deep differences between JSON payloads locally.
Generate UUIDv4 tokens and compute MD5, SHA-256, and SHA-512 cryptographic hashes.
NoPayWall calculates relative luminance according to the official W3C formula ((L1 + 0.05) / (L2 + 0.05)), evaluating exact contrast ratios for standard and large text under WCAG 2.1 AA and AAA standards.
Extract distraction-free reading views from cluttered, ad-heavy web pages.
Format, validate, beautify, and inspect deep differences between JSON payloads locally.
Generate UUIDv4 tokens and compute MD5, SHA-256, and SHA-512 cryptographic hashes.
Test and debug regular expressions with live visual highlighting and zero-width loop protection.