ColorSift is a free colour toolbox for designers and developers. It covers three things: interactive tools that do a specific job well, a reference library of the colour systems people actually work in, and writing about how colour behaves.
There are 23 tools, a 24-page reference section, a glossary of 63 terms, a library of 500+ named colours, curated palettes and gradients, and an archive of articles. Nothing is gated, nothing requires an account, and no colour you paste is sent anywhere — the tools run entirely in your browser.
Alex Pate is a professional web designer and developer. He builds and maintains ColorSift, and writes most of what is published here.
Named colours, Tailwind, Material, Pantone, RAL, Bootstrap and Apple system palettes are stored as structured data in the repository rather than fetched at runtime, so every value on the site is the same one the page was built from. Conversions between HEX, RGB, HSL, CMYK, LAB, OKLCH and the rest are computed in the browser from first principles, not looked up.
Contrast results follow the WCAG 2.1 relative-luminance formula. Where a tool reports a pass or fail, it is reporting against the published thresholds — 4.5:1 for normal text at AA, 7:1 at AAA — and not a house judgement.
If something here is wrong, it is worth telling us about — colour reference data is exactly the kind of thing that quietly rots. The contact page has the details.