Appainter
Adjust a Flutter Material theme from a seed color, compare the component preview, and export the settings as JSON.
What does Appainter do?
Appainter is a Flutter Material theme editor. Its Basic tab provides a seed color and color fields alongside a preview of buttons and other components, so you can compare the result as you make changes.
We tested colors and JSON export for a light Material 3 theme, not the individual component settings in Advanced.
Why it is useful
Color values alone do not show how a set of components will look together. Compare primary colors, container colors, and buttons in the preview before bringing the settings into a project.
Good fit for
Developers choosing colors for Flutter interfaces, designers discussing Material themes with engineers, and people learning how a seed color affects component appearance.
Try it when
In Basic, we kept Material 3 enabled and the theme light, then selected the Red [500] swatch. The seed color became #F44336, Primary changed to #904A42, and the button preview updated.
Export produced appainter_theme.json. It parsed as JSON, with useMaterial3 set to true, brightness to light, and colorScheme.primary to #ff904a42.
Before using it
Our export was JSON, not a theme already validated in an application. The official usage guide shows loading it with json_theme and warns that Flutter versions can affect compatibility. We did not test Advanced, JSON import, dark themes, fonts, or integration into a Flutter project.
