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Color Toolkit – Contrast Ratio Calculator
x402
Color Toolkit – Contrast Ratio Calculator is a paid API for AI agents from color.openverbs.com, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-14).
Computes the contrast ratio between a foreground (text) color and a background color to assess accessibility compliance
Price / call$0.002
Success—
StatusUnknown
How this service works
Compute the WCAG 2.1 contrast ratio between two colors and whether it passes AA/AAA.
Output
Returns the computed contrast ratio between the two specified colors (foreground and background), typically as a numeric ratio (e.g. 4.5:1), along with an indication of whether the pair passes WCAG AA or AAA accessibility thresholds for normal and large text.
Example use cases
WCAG compliance check for brand colors
“I'm designing a website and need to know if my brand's navy blue background (#003366) with white text (#FFFFFF) passes WCAG contrast requirements — can you check the contrast ratio?”
Accessibility audit for dark mode UI
“Check whether light gray text (#CCCCCC) on a dark charcoal background (#2B2B2B) has sufficient contrast ratio for our dark mode design to be accessible.”
Button label readability check
“Does the text color #F57C00 (orange) on a white (#FFFFFF) background have enough contrast to be readable on my call-to-action buttons?”
Technical details
Endpoint
POSThttps://color.openverbs.com/v1/contrastWhen to prefer
Choose this endpoint when you need a fast, programmatic contrast ratio calculation between exactly two colors — foreground and background — especially for WCAG accessibility compliance checks in UI/UX workflows, design audits, or automated accessibility testing pipelines. Prefer it over manual tools when integrating color accessibility validation into an agent-driven design or code review workflow.
Side effects
- Invalid or unrecognized color format for foreground or background (e.g. malformed hex, unsupported color name) returns an error
- Missing required fields (foreground or background) returns a validation error
- Extreme edge cases like transparent or undefined colors may return an error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object |
Tags
x402
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