About ColorLab

An open-source color science toolkit for designers and developers.

What is ColorLab?

ColorLab is a color palette generation and accessibility checking tool built on pure color science. No external APIs, no subscriptions — everything runs on your own server.

Choose a seed color and instantly get harmonious palettes based on color theory: complementary, analogous, triadic, split-complementary, tetradic, or simple lightness shades. Export as CSS variables or JSON.

Features

  • 🎨 6 harmony modes — Complementary, Analogous, Triadic, Split-Comp, Tetradic, Shades
  • 📋 CSS variable export — One-click copy of CSS custom properties
  • ♿ WCAG contrast checker — AA/AAA compliance for any two colors
  • 🔌 REST API — Integrate into any app via OpenAPI
  • 🚀 Self-hostable — Single docker-compose up

API

ColorLab exposes a REST API. Browse the interactive docs:

Open API Docs →

Quick example

curl -X POST https://colorlab.arcanumlabs.app/api/palette \
  -H "Content-Type: application/json" \
  -d '{"color": "#6366f1", "mode": "triadic"}'

Tech Stack

Backend

Python + FastAPI

Frontend

Jinja2 + Tailwind CSS

Rate Limiting

Redis sliding window

Color Math

Python colorsys

Container

Docker Compose

License

MIT