A quick look at one of the small Android apps I'm building solo, with .NET MAUI, under Horizon Software.
Every designer and developer has done this: found a colour they like, then spent twenty minutes squinting at a colour wheel trying to work out what goes with it — and another ten converting the result into whatever format the project needs. Tintbox is a free Android app that collapses both jobs into a few taps. Pick a colour, get a palette built on real colour theory, check it for accessibility, and export it straight into your codebase. It works completely offline, with no account.
Start with one colour, get a palette
Type an exact HEX, RGB or HSL value, or drag the sliders until it looks right. Tintbox then builds the classic colour-theory harmonies around it — complementary, analogous, triadic, monochromatic and tetradic — so you can see five credible directions instead of guessing at one. Tap any swatch to copy it as HEX, rgb(...) or hsl(...).
Steal a palette from a photo
Some of the best palettes are already out in the world — a shopfront, a sunset, a book cover. Point Tintbox at a photo from your camera or gallery and it pulls a palette out of the image. Need one specific colour rather than a whole scheme? The eyedropper samples the exact value of any single pixel you tap.
Accessibility built in, not bolted on
A palette that looks lovely and fails contrast is a palette you will have to redo. Tintbox includes a WCAG contrast checker — pick any two colours and see the contrast ratio with clear AA and AAA pass/fail marks for both normal and large text. There is also a colour-blindness simulator, so you can preview a palette as it appears with protanopia, deuteranopia and tritanopia before you commit to it.
Export straight into your project
This is the part that saves the most time. Tintbox turns a palette into actual code in 17 formats: CSS custom properties, SCSS, Less, CSS @theme (Tailwind v4), Tailwind config, JSON, W3C Design Tokens, SwiftUI, Jetpack Compose, Flutter, Android colours XML, MAUI XAML, GIMP/Inkscape .gpl, SVG swatches, and raw HEX, RGB and HSL lists. You can tidy the output as it comes — semantic colour names, hex casing and indentation. CSS and SCSS are always free; the full set unlocks with a single short video.
Or start from something designed
Some days you do not want to generate anything. Tintbox ships with thirty hand-picked palette packs — Coastal, Cyberpunk, Autumn Harvest, Retro and plenty more — for when you would rather begin with a palette someone has already balanced.
What you get
- Precise HEX, RGB and HSL entry, plus sliders
- Five harmony types from any base colour
- Palette extraction from any photo, plus a pixel eyedropper
- WCAG contrast checker with AA and AAA marks
- Colour-blindness simulator (protanopia, deuteranopia, tritanopia)
- Export to 17 developer formats, with a prettifier
- Thirty curated palette packs
- A local palette library with full ZIP backup and restore
- Works fully offline — no account, no sign-up
- Free to download
Get it on Google Play
Want the quick tour first? See the Tintbox app page.
Frequently asked questions
Is Tintbox free?
Yes — Tintbox is free to download from Google Play. CSS and SCSS export are always free, and the full set of 17 formats unlocks with a single short video.
Does it work offline?
Completely. There is no account and no sign-up, and every palette you make stays on your device.
Can I get a palette out of a photo?
Yes. Take a photo or pick one from your gallery and Tintbox extracts a palette from it — or use the eyedropper to sample one exact pixel.
Which export formats are supported?
Seventeen, including CSS custom properties, SCSS, Less, Tailwind (config and v4 @theme), JSON, W3C Design Tokens, SwiftUI, Jetpack Compose, Flutter, Android XML, MAUI XAML, GIMP/Inkscape and SVG swatches.
Can it check colour contrast?
It can. Pick any two colours and Tintbox shows the WCAG contrast ratio with AA and AAA pass/fail marks for normal and large text, and can simulate three types of colour blindness.
Built with .NET MAUI by Horizon Software. A small indie studio making simple, focused Android apps.
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