Tools

Utilities we reach for in audits, plus a quick WCAG contrast check you can run without leaving the site. Explore our performance, accessibility, green web, security, and SEO hubs for deeper reading.

WCAG contrast checker

Enter two sRGB hex colors. We use the same relative luminance formula as WCAG 2.x (normal text: 4.5:1 AA, 3:1 for large text; 7:1 / 4.5:1 for AAA).

17.85 : 1

Foreground

Background

AA — normal text (4.5:1) Pass

AA — large text (3:1) Pass

AAA — normal text (7:1) Pass

AAA — large text (4.5:1) Pass

Sample heading

Preview how body copy might look with this pair. Adjust colors above.

Performance

PageSpeed Insights
Lab + field data from Lighthouse for any public URL.
WebPageTest
Filmstrip, waterfalls, and multi-location runs.
Bundlephobia
Check npm package size and dependency cost before you install.
Chrome DevTools
Performance panel, coverage, and memory tooling in the browser.

Accessibility

WAVE
Visual feedback on structure, contrast, and ARIA on live pages.
axe DevTools
Browser extension and APIs used in many CI pipelines.
Accessibility Insights
Fast checks and guided assessments from Microsoft.
Pa11y
CLI and dashboard-friendly automated accessibility testing.

Green web

Website Carbon Calculator
Rough CO₂ estimate per page view and hosting context.
Green Web Foundation
Directory and APIs for green hosting verification.
Ecograder
Sustainability score with actionable recommendations.

Security

Security Headers
Quick report on HSTS, CSP, and related response headers.
Mozilla Observatory
HTTP Observatory scan with a simple letter grade.
Qualys SSL Labs
Deep TLS configuration and certificate chain analysis.

SEO & structured data

Rich Results Test
Validate structured data Google can use for rich results.
Schema Markup Validator
Schema.org validation for JSON-LD, Microdata, and RDFa.
Bing URL Inspection
See how Bing crawls and indexes a URL.