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WCAG Color Contrast Ratio Checker
x402
WCAG Color Contrast Ratio Checker is a paid API for AI agents from agent402.tools, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-15).
Computes the WCAG 2.x contrast ratio between a foreground and background color and returns AA/AAA pass/fail results for normal and large text.
Price / call$0.001
Success—
StatusUnknown
How this service works
Compute the WCAG 2.x contrast ratio between two colors (hex #rgb or #rrggbb) and whether it passes AA/AAA for normal and large text. Deterministic — for accessible color choices without a tool in the loop.
Output
Returns the numeric WCAG 2.x contrast ratio and boolean pass/fail results for AA (4.5:1 normal, 3:1 large) and AAA (7:1 normal, 4.5:1 large) conformance levels for both normal and large text sizes.
Example use cases
Example prompt
“What's the WCAG contrast ratio between a background of #1a1a2e and foreground text of #e0e0e0 — does it pass AA and AAA for both normal and large text?”
Technical details
Endpoint
POSThttps://agent402.tools/api/color-contrastWhen to prefer
Use this endpoint when you need a deterministic, standards-compliant WCAG 2.x contrast ratio calculation without relying on a vision model or manual lookup — especially useful in design automation pipelines, accessibility audits, or CI checks for UI components.
Side effects
- Invalid hex color format returns a 400 error
- Missing foreground or background field returns validation error
- Malformed #rgb shorthand not expanded correctly may cause parse error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| background | string | background color (#rgb or #rrggbb) |
| foreground | string | text color (#rgb or #rrggbb) |
Output
Schema · Response
{
"type": "json",
"example": {
"AA": {
"large": true,
"normal": false
},
"AAA": {
"large": false,
"normal": false
},
"ratio": 4.48
}
}Tags
x402
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