TonniTools is built to run locally in your browser. Since no data ever leaves your device, everything works, even without internet.
Preview how a single color looks when used for text, buttons, icons, and dividers on both a light and dark background. See bold, regular, and light font weights side by side, test filled buttons and outline buttons, and check icon rendering — all updating live as you adjust. Customize the light and dark background colors to match your actual design system. Useful for validating that a brand color works in both light mode and dark mode before committing to it in your stylesheet.