ColorBox

ColorBox is a palette-building tool for people creating color systems who need to check contrast and carry colors into design or code workflows. Its strongest case is a free, ad-free toolkit with dark-mode variants and several export routes; the main caveat is that some design handoffs require workarounds.

Overview

ColorBox lets users adjust multiple colors in one tab and share a system as a URL or JSON. That makes it more useful for building a coordinated palette than for picking a single isolated color. Hue progression can run in either direction, and the HSV and OKLCH modes give users two ways to work with color.

Key features

Contrast indicators show 3:1, 4.5:1, and 7:1 levels across color sets. That gives designers a practical accessibility check while refining a palette, rather than leaving contrast as a separate final task.

Auto Dark Mode generates an inverted set from the original inputs; users can also duplicate a set and edit the inversion themselves. Automatic generation is a quick starting point, while manual edits allow more control over the result. Custom curves, however, were not yet available in ColorBox as described, limiting users who want to shape hue progression with their own curves.

Export choices include Config, Output, Tailwind, CSS, OKLCH, and Swift. The maker also describes using exported JSON with the color algorithm through NPM to generate colors in code. Figma users can import a system through a plugin and JSON, customize step names, and generate Paint Styles. The Sketch route is less direct: it goes through the Figma plugin, then SVG export, then import into Sketch.

Pricing

ColorBox’s Free plan costs nothing and is free to use without ads. Palette generation and accessibility checks are included. There is no free trial because the product is free; no paid plan or seat-based restriction is part of this offer. For users who need palette creation, contrast checks, and export options, the zero-cost plan avoids a subscription decision.

Platforms

ColorBox is available on the web and as an extension. Its Figma workflow is plugin-based; Sketch users can reach the app through the multi-step SVG workaround rather than a direct Sketch route.

Who it's for

ColorBox suits designers and developers building multi-color systems who want contrast indicators, dark-mode variants, and exports that connect to common design and code workflows. It is less suitable for teams that need custom curve controls in the app or a direct Sketch handoff.

Pros and cons

• Pros: Free and ad-free, with palette generation and contrast indicators in the same workflow.
• Pros: Dark-mode generation, editable inverted sets, and exports spanning CSS, Tailwind, OKLCH, Swift, and more support both design and implementation.
• Cons: Custom curves were not yet available in the app, so hue progression cannot be shaped that way.
• Cons: Sketch export depends on a Figma-and-SVG detour, adding steps for Sketch-centered work.

Alternatives

For a wider comparison of palette tools, browse Color Palette Generators.

Choose Pantone Connect Palette Generator if access to more than 15,000 colors and its Search, Pick, and Measure tools matter more; its free Basic plan requires an account and supports saving and sharing up to 10 palettes.

Color Palette Generator AI is a fit for users who prioritize unlimited generations, every export format, shareable links, and API access without an account.

Windows users looking for free, open-source software can consider Colora. ColorDesigner offers a free tier with ads, 12 tools, limited saved colors and palettes, one project, and HEX export. Colorfool is another free web option, with accessibility checks not paywalled.

ColorKit is another free color-tools option. ColorMagic offers free web and API access and says palette generation is unlimited, though the site may show ads. ColorPalette Pro is a free web alternative whose maker says ads or subscriptions are not planned.

Verdict

Choose ColorBox if you want a free, ad-free way to build and share color systems, check contrast, create dark-mode variants, and export into design or code workflows. Look elsewhere if custom curves are essential or you need a direct Sketch workflow.