Colorise Pro

Colour API

GET /api/color/{hex} describes one colour. The sample below is #2563eb, computed by the same functions as the colour pages. The response is noindex.

curl https://colorise.pro/api/color/2563eb

Name: Old Gungeon Red (nearest)
OKLCH: oklch(0.546 0.215 262.9)
On white: 5.16:1 · APCA Lc 75
On black: 4.06:1 · APCA Lc -27

Fields

name, exact — the colour's own name, or the nearest named colour when it has none.
hex, rgb, hsl, oklch, lab.
contrast.white and contrast.black — WCAG ratio (floored label) and signed APCA Lc, with this colour as the text.
nearest — up to eight named colours by OKLab distance.
tints and shades — nine steps toward white and black.

Over the limit the status is 429, with Retry-After and X-RateLimit-Remaining. A bad hex is 400 invalid_hex.

Questions

Do I need a key?

No. The route is public, sends CORS headers, and is limited to 60 requests a minute per IP. There is no service-level agreement.

Which hex forms work?

Three or six digits, any case. An optional leading # is stripped. Anything else, including eight-digit alpha, returns 400 invalid_hex.

What does APCA Lc mean here?

The colour is the text and the background is white or black. A positive Lc is dark text on a light background. The value is rounded. It is not a legal accessibility audit.

Browse colours

Color tools for developers

A color API without the ceremony

Every well-known color has a stable URL and a JSON representation: conversions between HEX, RGB, HSL, OKLCH and the Display P3 coordinates, the nearest named color, and contrast data against black and white. If your code needs to answer “what is this color, what does it convert to, and can text sit on it”, the API answers in one request, computed with the same engine as the tools on this site.

Tokens: CSS, Tailwind and DTCG

Design tokens are the contract between design and code. The tools here export the formats teams actually commit: CSS custom properties with oklch() values and sRGB fallbacks, Tailwind theme extensions, and W3C DTCG JSON for Style Dictionary pipelines. Generate a palette in Studio or pick one from the library and the export keeps color names, ramp steps and semantic roles intact.

Contrast failures are cheapest before they ship. The same WCAG ratio and APCA calculations behind the contrast checker are available per color, so a CI step can assert that your token pairs stay above your chosen threshold when the palette changes. The WCAG vs APCA guide explains which metric to gate on today (WCAG 2.2 for compliance, APCA as an additional readability check).

Colour API

GET /api/color/{hex} describes one colour. The sample below is #2563eb, computed by the same functions as the colour pages. The response is noindex.

curl https://colorise.pro/api/color/2563eb

Name

Old Gungeon Red (nearest)

OKLCH

oklch(0.546 0.215 262.9)

On white

5.16:1 · APCA Lc 75

On black

4.06:1 · APCA Lc -27

Fields

name, exact — the colour's own name, or the nearest named colour when it has none.

hex, rgb, hsl, oklch, lab.

contrast.white and contrast.black — WCAG ratio (floored label) and signed APCA Lc, with this colour as the text.

nearest — up to eight named colours by OKLab distance.

tints and shades — nine steps toward white and black.

Over the limit the status is 429, with Retry-After and X-RateLimit-Remaining. A bad hex is 400 invalid_hex.

Questions

Do I need a key?

No. The route is public, sends CORS headers, and is limited to 60 requests a minute per IP. There is no service-level agreement.

Which hex forms work?

Three or six digits, any case. An optional leading # is stripped. Anything else, including eight-digit alpha, returns 400 invalid_hex.

What does APCA Lc mean here?

The colour is the text and the background is white or black. A positive Lc is dark text on a light background. The value is rounded. It is not a legal accessibility audit.

Color tools for developers

Colour API

Fields

Questions

Do I need a key?

Which hex forms work?

What does APCA Lc mean here?

Color tools for developers

A color API without the ceremony

Tokens: CSS, Tailwind and DTCG

Accessibility checks in the pipeline

Colour API

Fields

Questions

Do I need a key?

Which hex forms work?

What does APCA Lc mean here?

Color tools for developers

A color API without the ceremony

Tokens: CSS, Tailwind and DTCG

Accessibility checks in the pipeline