Convert colors, check WCAG and APCA contrast, build palettes, gradients and tokens.
PickShade API is a free Art & Design API that requires no API key, is served over HTTPS and supports CORS, so it can be called from the browser.
Free REST API for colors with OpenAPI spec: convert between HEX, RGB, HSL and OKLCH, check WCAG 2 and APCA contrast, generate scales and palettes, export Tailwind and DTCG tokens.
Details from pickshade.com.

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The PickShade API is provided by PickShade (pickshade.com). Free REST API for colors with OpenAPI spec: convert between HEX, RGB, HSL and OKLCH, check WCAG 2 and APCA contrast, generate scales and palettes, export Tailwind and DTCG tokens.
Yes. The PickShade API is listed in the Art & Design category of the public-apis directory, which only includes APIs that are free or have a free tier. Check its documentation for rate limits and paid plans.
No. The PickShade API requires no authentication, so you can start making requests without signing up.
Yes. The PickShade API supports CORS, so front-end JavaScript can call it directly.
Yes. The PickShade API is served over HTTPS, so it's safe to use in production.