Colour utilities: ?op=convert (default) turns any hex/rgb()/hsl()/CSS-name into hex, rgb,
Colour utilities: ?op=convert (default) turns any hex/rgb()/hsl()/CSS-name into hex, rgb, hsl, hsv, alpha, relative luminance and exact CSS name; ?op=contrast with ?fg=&bg= returns the WCAG 2.x contrast ratio and AA/AAA pass/fail for normal & large text plus UI components (accessibility / EAA); ?op=palette derives complementary, analogous, triadic, tints and shades. Send hex without '#'.
1000 (raw units)
price
6
calls / 30d
5
unique payers
2026-09-17
updated
Provider
402utils.com · discovered, not yet claimed by its owner
Payment (x402 accepts[])
[
{
"scheme": "exact",
"network": "eip155:8453",
"payTo": "0xc55A2D530b53CBaD1001e4AfD4720B7E71f9C291",
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"amount": "1000",
"maxTimeoutSeconds": 60
}
]Output schema
{
"bazaar": {
"info": {
"input": {
"method": "GET",
"queryParams": {
"bg": "ffffff",
"fg": "000000",
"op": "contrast"
},
"type": "http"
},
"output": {
"example": {
"AA": {
"largeText": true,
"normalText": true,
"uiComponents": true
},
"AAA": {
"largeText": true,
"normalText": true
},
"bg": {
"hex": "#ffffff",
"input": "ffffff"
},
"fg": {
"hex": "#000000",
"input": "000000"
},
"op": "contrast",
"ratio": 21
},
"type": "json"
}
},
"schema": {
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"method": {
"enum": [
"GET"
],
"type": "string"
},
"queryParams": {
"description": "Query string only.",
"properties": {
"bg": {
"description": "Background colour (op=contrast). Falls back to `color` for fg.",
"type": "string"
},
"color": {
"description": "The colour (convert/palette): hex without '#', rgb(), hsl() or a CSS name.",
"type": "string"
},
"fg": {
"description": "Foreground colour (op=contrast).",
"type": "string"
},
"op": {
"default": "convert",
"enum": [
"convert",
"contrast",
"palette"
],
"type": "string"
}
},
"type": "object"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"description": "Shape depends on `op`.",
"properties": {
"AA": {
"description": "AA pass/fail for normalText, largeText, uiComponents.",
"type": "object"
},
"AAA": {
"description": "AAA pass/fail for normalText, largeText.",
"type": "object"
},
"analogous": {
"items": {
"type": "string"
},
"type": "array"
},
"complementary": {
"description": "(op=palette).",
"type": "string"
},
"hex": {
"type": "string"
},
"hsl": {
"type": "object"
},
"hsv": {
"type": "object"
},
"luminance": {
"description": "WCAG relative luminance 0-1 (op=convert).",
"type": "number"
},
"name": {
"description": "Exact CSS colour name, if any.",
"type": [
"string",
"null"
]
},
"op": {
"type": "string"
},
"ratio": {
"description": "WCAG contrast ratio 1-21 (op=contrast).",
"type": "number"
},
"rgb": {
"type": "object"
},
"shades": {
"items": {
"type": "string"
},
"type": "array"
},
"tints": {
"items": {
"type": "string"
},
"type": "array"
},
"triadic": {
"items": {
"type": "string"
},
"type": "array"
}
},
"required": [
"op"
],
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}
}
}Use it
curl
curl "https://402utils.com/v1/color" # -> 402 Payment Required, accepts[] lists how to pay # retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid
JavaScript
const res = await fetch("https://402utils.com/v1/color");
if (res.status === 402) {
const { accepts } = await res.json();
// pay one of accepts[] via an x402 client, then retry with the payment header
}Python
import httpx
res = httpx.get("https://402utils.com/v1/color")
if res.status_code == 402:
accepts = res.json()["accepts"]
# pay one of accepts[] via an x402 client, then retry with the payment headerMachine-readable
Everything on this page is also available as clean JSON at /resources/5891.json, and this resource appears in /discovery/resources and /discovery/search.