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Color Contrast Ratio Checker
x402
Color Contrast Ratio Checker is a paid API for AI agents from agent-data-tools.revmesh2074.workers.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-23).
Calculates the WCAG contrast ratio between a foreground (text) color and background color, returning AA and AAA accessibility pass/fail results.
Price / call$0.01
Success—
StatusUnknown
How this service works
WCAG 2 contrast ratio between a text colour and a background colour, with pass/fail for AA and AAA at normal and large text sizes. Use to check that a design is readable.
Output
Returns a JSON object with the numeric contrast ratio (e.g. 4.54) and four boolean flags: aaLarge, aaNormal, aaaLarge, and aaaNormal — indicating whether the color pair passes WCAG 2.1 AA and AAA thresholds for large and normal text respectively.
Example use cases
Brand color accessibility audit
“I'm designing a website using our brand colors — dark navy #0D2B4E as the background and cream #F5F0E8 as the text color. Can you check if that combination meets WCAG AA and AAA accessibility standards?”
UI dark mode contrast check
“My dark mode theme uses #121212 as the background and #B0BEC5 as the text color — does that pass WCAG AA contrast requirements for normal-sized body text?”
Design system compliance validation
“Before we ship, can you verify that our button label color #FFFFFF on our primary button background #E53935 passes WCAG AA contrast for large text?”
Technical details
Endpoint
GEThttps://agent-data-tools.revmesh2074.workers.dev/color/contrast?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need a fast, no-account-required programmatic WCAG contrast ratio check paid per-call in USDC. Ideal for AI agents automating accessibility audits, design system validation pipelines, or one-off color pair checks without setting up a dedicated accessibility API key.
Side effects
- Missing fg or bg query parameters returns an error
- Invalid or malformed color strings (non-hex, unsupported formats) may return an error or unexpected ratio
- Very similar colors return low ratios and all false flags
- Payment failure (402) if USDC balance insufficient — call is not charged on failure
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| bgrequired | string | Background colour |
| fgrequired | string | Text colour |
Output
Schema · Response
| Field | Type | Description |
|---|---|---|
| ratio | number | |
| aaLarge | boolean | |
| aaNormal | boolean | |
| aaaLarge | boolean | |
| aaaNormal | boolean |
Tags
x402
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