Color Format Conversion

Convert color values between HEX, RGB, HSL, and CMYK formats. Every response includes all four representations so you never need to call more than once.

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Overview

Use Cases

Convert design tool color exports into CSS-ready values
Build color palette generators and pickers
Normalize color inputs from different user sources into a single format
Populate design system tokens from brand color values
Inspect color relationships between HEX codes and their HSL equivalents

Features

Converts between HEX, RGB, HSL, and CMYK in a single call

Returns all four formats simultaneously — no need for multiple requests

Accepts shorthand HEX notation (e.g. "#f53" → "#ff5533")

Flexible input parsing — whitespace-tolerant for rgb() and hsl() strings

Zero external dependencies — fast, in-memory conversion

API Endpoints

Convert Color

Convert a color value from one format to another. The response always includes all four formats.

GET

https://api.requiems.xyz/v1/convert/color

Parameters

Name	Type	Required	Description
from	`string`	Required	Source color format: hex, rgb, hsl, or cmyk
to	`string`	Required	Target color format: hex, rgb, hsl, or cmyk
value	`string`	Required	Color value in the source format (e.g. #ff5733, rgb(255,87,51), hsl(11,100%,60%), cmyk(0%,66%,80%,0%))

Try it out

Live Demo

Request

from * (string)

Source color format: hex, rgb, hsl, or cmyk

to * (string)

Target color format: hex, rgb, hsl, or cmyk

value * (string)

Color value in the source format (e.g. #ff5733, rgb(255,87,51), hsl(11,100%,60%), cmyk(0%,66%,80%,0%))

Response Fields

Field	Type	Description
input	`string`	The original value passed in the value parameter
result	`string`	The color expressed in the requested to format
formats.hex	`string`	HEX representation (#rrggbb)
formats.rgb	`string`	RGB representation (rgb(r, g, b))
formats.hsl	`string`	HSL representation (hsl(h, s%, l%))
formats.cmyk	`string`	CMYK representation (cmyk(c%, m%, y%, k%))

Code Examples

# HEX to HSL
curl "https://api.requiems.xyz/v1/convert/color?from=hex&to=hsl&value=%23ff5733" \
  -H "requiems-api-key: YOUR_API_KEY"

# RGB to CMYK
curl "https://api.requiems.xyz/v1/convert/color?from=rgb&to=cmyk&value=rgb(255%2C87%2C51)" \
  -H "requiems-api-key: YOUR_API_KEY"

# HSL to HEX
curl "https://api.requiems.xyz/v1/convert/color?from=hsl&to=hex&value=hsl(120%2C100%25%2C50%25)" \
  -H "requiems-api-key: YOUR_API_KEY"

import requests

url = "https://api.requiems.xyz/v1/convert/color"
headers = {"requiems-api-key": "YOUR_API_KEY"}
params = {"from": "hex", "to": "hsl", "value": "#ff5733"}

response = requests.get(url, params=params, headers=headers)
data = response.json()["data"]

print(data["result"])          # hsl(11, 100%, 60%)
print(data["formats"]["rgb"])  # rgb(255, 87, 51)

const params = new URLSearchParams({
  from: 'hex',
  to: 'hsl',
  value: '#ff5733'
});

const response = await fetch(
  `https://api.requiems.xyz/v1/convert/color?${params}`,
  { headers: { 'requiems-api-key': 'YOUR_API_KEY' } }
);

const { data } = await response.json();
console.log(data.result);           // hsl(11, 100%, 60%)
console.log(data.formats.cmyk);     // cmyk(0%, 66%, 80%, 0%)

require 'net/http'
require 'json'

uri = URI('https://api.requiems.xyz/v1/convert/color')
uri.query = URI.encode_www_form(from: 'hex', to: 'hsl', value: '#ff5733')

request = Net::HTTP::Get.new(uri)
request['requiems-api-key'] = 'YOUR_API_KEY'

response = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) do |http|
  http.request(request)
end

data = JSON.parse(response.body)['data']
puts data['result']            # hsl(11, 100%, 60%)
puts data['formats']['hex']    # #ff5733

Error Responses

bad_request

One or more of from, to, or value parameters is missing or the from/to value is not one of: hex, rgb, hsl, cmyk.

invalid_color

The value cannot be parsed in the specified from format.

internal_error

Unexpected server error.

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