What it does
SassMe visualises the HSL colour functions lighten, darken, saturate, desaturate and adjust-hue in a browser. Jim Nielsen’s repository is the official successor to the earlier Arc90 project.
Enter a six-character hex colour and adjust the function values. Lightness and saturation controls run from 0 to 100; hue adjustment runs from -360 to 360. The resulting swatch, hex value and Sass expression show the effect of the chosen transformation.
A URL can carry the starting colour and adjustments, allowing the same combination to be reopened. At the limits, HSL values are clamped: darkening an already dark colour far enough produces black.
These are legacy Sass functions. Sass deprecated them from Dart Sass 1.79.0 in favour of its colour module. Current Sass work should use the corresponding module operations, such as color.adjust with an explicit HSL space; SassMe remains useful for understanding the older transformations.
Strengths
- A transformation is shown as a swatch, hex value and Sass expression.
- URL parameters can carry a starting colour and adjustments.
Watch out for
- The demonstrated global colour functions are deprecated in modern Dart Sass.
Best for
- Learning the behaviour of legacy Sass HSL transformations.
Sources
- GitHub - jimniels/sassme: SassMe: Real-time manipulation and visualization of Sass color functions · GitHub (Oct 28, 2026)
- SassMe v2.0 - Jim Nielsen’s Blog (Oct 28, 2026)
- Sass: Breaking Change: Color Functions (Oct 28, 2026)
- sassme/package.json at master · jimniels/sassme · GitHub (Oct 28, 2026)