WCAG contrast ratio calculator, accessibility checker, color contrast, a11y, WCA
WCAG contrast ratio calculator, accessibility checker, color contrast, a11y, WCAG 2.1 AA AAA, text contrast, color blindness, readable text color. Calculate WCAG 2.1 contrast ratio between two colors and return pass/fail for AA/AAA at normal/large text sizes. Accepts payment on Base or Solana — either network works.
Answeringour last check, 2026-09-24
1 of 1checks answered this week
472 msmedian answer time
$0.008listed price per call
$0.008price it asked us
Paid test badge: not yet. The checks above are free: we call the tool without paying and read the payment request it sends back. The Verified badge needs paid calls whose answers match the promised output, and nobody can buy a badge.
Endpoint
GET https://api.x402node.dev/color/contrast
| Category | Market data |
|---|---|
| Provider host | api.x402node.dev |
| Networks | eip155:8453, solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp |
| Payment schemes | exact |
| Self-reported calls, 30 days | 1 from 1 payers (the provider's figure, not ours) |
Our checks, last 30 days
| Day | Result | HTTP | Asked | Time |
|---|---|---|---|---|
| 2026-09-24 | valid payment request | 402 | $0.008 | 472 ms |
Example input (from the provider)
{
"method": "GET",
"queryParams": {
"bg": "string",
"fg": "string"
},
"type": "http"
}
Promised output schema (from the provider)
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"method": {
"enum": [
"GET"
],
"type": "string"
},
"queryParams": {
"properties": {
"bg": {
"description": "Background color (optional)",
"type": "string"
},
"fg": {
"description": "Foreground color (required)",
"type": "string"
}
},
"required": [
"fg"
],
"type": "object"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}