Clean.tools Color API
Color conversion, palettes, and accessibility — deterministic.
Work with this as data
Every API here is available over the APIs.io API and to AI agents over MCP.
MCP server
One button, every client — Claude, Cursor, VS Code and the rest.
https://apis.io/mcp
Tools for apis
7 MCP tools reach this
find_apisBrowse and filter every API in the catalog.get_api_artifactsOne API's artifacts, grouped by type.get_openapiThe primary OpenAPI for this API.find_similar_apisAPIs that look like this one.apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.resolveTurn a domain, URL or GitHub org into the provider it belongs to.find_cohortsEvery scored population of providers in the catalog.
Call it yourself
curl for this page
This API
curl "https://apis.io/api/v1/apis/clean-tools:clean-tools-color-api"
All apis
curl "https://apis.io/api/v1/apis?limit=25"Calls without X-API-Key need no key. Calls with it need a paid plan — get a key.
Get an API key
Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.
A second provider on the same verified email joins the account you already have.
OpenAPI Specification
openapi: 3.2.0
info:
title: Clean.tools Color API
version: 0.1.0
summary: Read-only developer, finance, date, and text utilities. No key, no signup.
description: 'Every endpoint is read-only and side-effect-free. Most tools are deterministic: same input, same output. The generator tools (uuid_v4, generate_id, random_number, generate_password) use cryptographic randomness instead. Requests are processed in memory and never written to storage or logs; only anonymous per-tool call counters are kept. The same tools are available over the Model Context Protocol at POST /mcp (mount a subset with ?tools=). Rate limit: about 60 requests/minute per caller — honor Retry-After on 429 and add jitter.'
license:
name: MIT
contact:
name: Clean.tools
url: https://clean.tools/
email: support@clean.tools
servers:
- url: https://api.clean.tools
tags:
- name: color
description: Color conversion, palettes, and accessibility — deterministic.
paths:
/v1/color_palette:
post:
operationId: color_palette
summary: Use this when you need color-harmony palettes derived from one base hex color
description: 'Use this when you need color-harmony palettes derived from one base hex color. Rotates hue/lightness in HSL to build complementary (+180 degrees), analogous (-30/+30), triadic (+120/+240), split-complementary (+150/+210), and monochromatic (lightness steps) swatch sets, each as an array of hex strings. Accepts a 6-digit hex with or without a leading ''#'' (case-insensitive). Deterministic: same input, same output. Example: {color:''#e11d48''} -> base ''#e11d48'', complementary [''#e11d48'',''#1de1b6''], monochromatic [''#590c1d'',''#9d1432'',''#e11d48'',''#eb607e'',''#f3a4b5'']. Note: grayscale inputs (e.g. ''#000000'') have no defined hue, so the hue-rotated sets are all identical and only the monochromatic lightness steps differ.'
x-read-only: true
tags:
- color
requestBody:
required: true
content:
application/json:
schema:
type: object
additionalProperties: false
properties:
color:
type: string
description: A 6-digit hex color, with or without a leading '#', e.g. "#e11d48" or "e11d48". Case-insensitive.
required:
- color
example:
color: '#e11d48'
responses:
'200':
description: Structured tool result.
content:
application/json:
schema:
type: object
properties:
tool:
type: string
result:
type: object
properties:
base:
type: string
description: Normalized base color as a 6-digit hex string (lowercased, with leading '#').
complementary:
type: array
items:
type: string
description: '[base, hue+180] — 2 hex swatches.'
analogous:
type: array
items:
type: string
description: '[hue-30, base, hue+30] — 3 hex swatches.'
triadic:
type: array
items:
type: string
description: '[base, hue+120, hue+240] — 3 hex swatches.'
splitComplementary:
type: array
items:
type: string
description: '[base, hue+150, hue+210] — 3 hex swatches.'
monochromatic:
type: array
items:
type: string
description: 5 hex shades stepping lightness by -30, -15, 0, +15, +30 from the base; the two darker steps are floored at lightness 5 and 10, and the two lighter steps capped at 90 and 95.
required:
- base
- complementary
- analogous
- triadic
- splitComplementary
- monochromatic
additionalProperties: false
example:
tool: color_palette
result:
base: '#e11d48'
complementary:
- '#e11d48'
- '#1de1b6'
analogous:
- '#e11daa'
- '#e11d48'
- '#e1541d'
triadic:
- '#e11d48'
- '#48e11d'
- '#1d48e1'
splitComplementary:
- '#e11d48'
- '#1de154'
- '#1daae1'
monochromatic:
- '#590c1d'
- '#9d1432'
- '#e11d48'
- '#eb607e'
- '#f3a4b5'
'400':
description: Invalid input or the tool reported an error.
content:
application/json:
schema:
type: object
required:
- error
properties:
error:
type: string
description: Human-readable, structured error message.
code:
type: string
description: Stable machine-readable error code.
tool:
type: string
description: Tool name, when the error is tool-specific.
'413':
description: Request body exceeds the 128 KB limit.
'429':
description: Rate limit exceeded; the response carries Retry-After and RateLimit-* headers — honor them and add jitter.
/v1/color_contrast:
post:
operationId: color_contrast
summary: Use this when checking whether a text/background color pair meets WCAG 2.x…
description: 'Use this when checking whether a text/background color pair meets WCAG 2.x accessibility contrast. Computes the relative-luminance contrast ratio (1-21, rounded to 2 decimals) and returns pass/fail booleans for normal and large text at AA and AAA levels (thresholds 4.5 / 7 / 3 / 4.5), plus a suggested passing foreground hex when normal-text AA fails (null when it already passes or none is found). Accepts 3- or 6-digit hex, with or without a leading ''#''; echoed colors are normalized to 6-digit hex. Deterministic: same input, same output. Example: {foreground:''777'', background:''fff''} -> ratio 4.48, normalAA false, largeAA true, suggestedForeground ''#767676''.'
x-read-only: true
tags:
- color
requestBody:
required: true
content:
application/json:
schema:
type: object
additionalProperties: false
properties:
foreground:
type: string
description: 'Foreground (text) color as a 3 or 6 digit HEX string, with or without a leading #, e.g. "#1a1a1a" or "777".'
background:
type: string
description: 'Background color as a 3 or 6 digit HEX string, with or without a leading #, e.g. "#ffffff" or "fff".'
required:
- foreground
- background
example:
foreground: '777'
background: fff
responses:
'200':
description: Structured tool result.
content:
application/json:
schema:
type: object
properties:
tool:
type: string
result:
type: object
properties:
foreground:
type: string
description: Normalized foreground color as a 6-digit hex string.
background:
type: string
description: Normalized background color as a 6-digit hex string.
ratio:
type: number
description: WCAG 2.x contrast ratio, 1 to 21, rounded to 2 decimals.
normalAA:
type: boolean
description: Unrounded ratio >= 4.5 (normal text, AA).
normalAAA:
type: boolean
description: Unrounded ratio >= 7 (normal text, AAA).
largeAA:
type: boolean
description: Unrounded ratio >= 3 (large text >=18pt / 14pt bold, AA).
largeAAA:
type: boolean
description: Unrounded ratio >= 4.5 (large text, AAA).
suggestedForeground:
type:
- string
- 'null'
description: A passing foreground hex (>=4.5 vs the background) when normal-text AA fails; null when the pair already passes or no passing value is found.
required:
- foreground
- background
- ratio
- normalAA
- normalAAA
- largeAA
- largeAAA
- suggestedForeground
additionalProperties: false
example:
tool: color_contrast
result:
foreground: '#777777'
background: '#ffffff'
ratio: 4.48
normalAA: false
normalAAA: false
largeAA: true
largeAAA: false
suggestedForeground: '#767676'
'400':
description: Invalid input or the tool reported an error.
content:
application/json:
schema:
type: object
required:
- error
properties:
error:
type: string
description: Human-readable, structured error message.
code:
type: string
description: Stable machine-readable error code.
tool:
type: string
description: Tool name, when the error is tool-specific.
'413':
description: Request body exceeds the 128 KB limit.
'429':
description: Rate limit exceeded; the response carries Retry-After and RateLimit-* headers — honor them and add jitter.
/v1/css_gradient:
post:
operationId: css_gradient
summary: Use this when you need a ready-to-paste CSS gradient value from 2-5 hex color…
description: 'Use this when you need a ready-to-paste CSS gradient value from 2-5 hex color stops. Builds a linear-gradient(...) (default; direction defaults to ''to bottom'') or a radial-gradient(circle, ...). Direction accepts keywords (''to right'', ''to left'', ''to top'', ''to bottom''), angles (''45deg'', ''90deg'', ''135deg''), or ''to ''; it is ignored for radial, and passing type ''radial'' (or direction ''radial'') forces a radial gradient. Colors accept 6-digit hex with or without a leading ''#'' and are echoed normalized in order. Deterministic: same input, same output. Example: {colors:[''#3b82f6'',''8b5cf6'']} -> css ''linear-gradient(to bottom, #3b82f6, #8b5cf6)'', type ''linear''. Radial results omit the ''direction'' field.'
x-read-only: true
tags:
- color
requestBody:
required: true
content:
application/json:
schema:
type: object
additionalProperties: false
properties:
colors:
type: array
items:
type: string
minItems: 2
maxItems: 5
description: 2 to 5 color stops as 6-digit hex strings, with or without a leading '#', e.g. ["#3b82f6", "8b5cf6"].
type:
type: string
enum:
- linear
- radial
description: Gradient type. Defaults to "linear". "radial" produces radial-gradient(circle, ...).
direction:
type: string
description: 'Linear direction: a keyword ("to right", "to left", "to bottom", "to top"), an angle ("45deg", "135deg", "90deg"), or "to <side> <side>". Defaults to "to bottom". Ignored for radial; passing "radial" here forces a radial gradient.'
required:
- colors
example:
colors:
- '#3b82f6'
- 8b5cf6
responses:
'200':
description: Structured tool result.
content:
application/json:
schema:
type: object
properties:
tool:
type: string
result:
type: object
properties:
css:
type: string
description: 'Ready-to-paste CSS gradient value, e.g. ''linear-gradient(to bottom, #3b82f6, #8b5cf6)'' or ''radial-gradient(circle, #3b82f6, #8b5cf6)''.'
type:
type: string
enum:
- linear
- radial
description: Resolved gradient type.
direction:
type: string
description: Resolved linear direction (keyword or angle). Present only for linear gradients; omitted for radial.
colors:
type: array
items:
type: string
description: Normalized 6-digit hex color stops, in input order.
required:
- css
- type
- colors
example:
tool: css_gradient
result:
css: 'linear-gradient(to bottom, #3b82f6, #8b5cf6)'
type: linear
direction: to bottom
colors:
- '#3b82f6'
- '#8b5cf6'
'400':
description: Invalid input or the tool reported an error.
content:
application/json:
schema:
type: object
required:
- error
properties:
error:
type: string
description: Human-readable, structured error message.
code:
type: string
description: Stable machine-readable error code.
tool:
type: string
description: Tool name, when the error is tool-specific.
'413':
description: Request body exceeds the 128 KB limit.
'429':
description: Rate limit exceeded; the response carries Retry-After and RateLimit-* headers — honor them and add jitter.
/v1/convert_color:
post:
operationId: convert_color
summary: Use this when you need one color's exact values across every common format
description: 'Use this when you need one color''s exact values across every common format. Accepts a hex (#abc or #aabbcc), rgb(r, g, b) with r/g/b 0-255, or hsl(h, s%, l%) color and returns hex, rgb {r,g,b}, hsl {h,s,l}, hsv {h,s,v}, cmyk {c,m,y,k}, and oklch {l,c,h} (CSS Color 4: sRGB -> linear -> OKLab -> OKLCH, rounded to 4 decimals). Note oklch.l is 0-1 (not 0-100) and hue is 0 for grays. Deterministic: same input, same output. Example: "#ff0000" -> oklch {l: 0.628, c: 0.2577, h: 29.2339}. Alpha channels are not supported.'
x-read-only: true
tags:
- color
requestBody:
required: true
content:
application/json:
schema:
type: object
additionalProperties: false
properties:
color:
type: string
description: 'A color as hex (#abc or #aabbcc), rgb(r, g, b) with r/g/b 0-255, or hsl(h, s%, l%). Alpha is not supported.'
required:
- color
example:
color: '#ff0000'
responses:
'200':
description: Structured tool result.
content:
application/json:
schema:
type: object
properties:
tool:
type: string
result:
type: object
additionalProperties: false
required:
- hex
- rgb
- hsl
- hsv
- cmyk
- oklch
properties:
hex:
type: string
description: 6-digit lowercase hex, e.g. '#ff0000'.
rgb:
type: object
additionalProperties: false
required:
- r
- g
- b
properties:
r:
type: integer
description: Red 0-255.
g:
type: integer
description: Green 0-255.
b:
type: integer
description: Blue 0-255.
hsl:
type: object
additionalProperties: false
required:
- h
- s
- l
properties:
h:
type: integer
description: Hue 0-360 degrees (0 for grays).
s:
type: integer
description: Saturation 0-100 percent.
l:
type: integer
description: Lightness 0-100 percent.
hsv:
type: object
additionalProperties: false
required:
- h
- s
- v
properties:
h:
type: integer
description: Hue 0-360 degrees.
s:
type: integer
description: Saturation 0-100 percent.
v:
type: integer
description: Value/brightness 0-100 percent.
cmyk:
type: object
additionalProperties: false
required:
- c
- m
- y
- k
properties:
c:
type: integer
description: Cyan 0-100 percent.
m:
type: integer
description: Magenta 0-100 percent.
y:
type: integer
description: Yellow 0-100 percent.
k:
type: integer
description: Key/black 0-100 percent.
oklch:
type: object
additionalProperties: false
required:
- l
- c
- h
properties:
l:
type: number
description: OKLCH lightness 0-1 (not 0-100), rounded to 4 decimals.
c:
type: number
description: OKLCH chroma, rounded to 4 decimals.
h:
type: number
description: OKLCH hue 0-360 degrees (0 for grays), rounded to 4 decimals.
example:
tool: convert_color
result:
hex: '#ff0000'
rgb:
r: 255
g: 0
b: 0
hsl:
h: 0
s: 100
l: 50
hsv:
h: 0
s: 100
v: 100
cmyk:
c: 0
m: 100
y: 100
k: 0
oklch:
l: 0.628
c: 0.2577
h: 29.2339
'400':
description: Invalid input or the tool reported an error.
content:
application/json:
schema:
type: object
required:
- error
properties:
error:
type: string
description: Human-readable, structured error message.
code:
type: string
description: Stable machine-readable error code.
tool:
type: string
description: Tool name, when the error is tool-specific.
'413':
description: Request body exceeds the 128 KB limit.
'429':
description: Rate limit exceeded; the response carries Retry-After and RateLimit-* headers — honor them and add jitter.
externalDocs:
description: LLM guide
url: https://api.clean.tools/llms.txt