CanDoYa Accessible Palette Generator vs Leonardo

CanDoYa Accessible Palette Generator is a free web and browser-extension tool that turns a brand color and page background into interface color roles. It generates text, muted text, surface, primary, on-primary, accent, and border colors, then checks intended foreground/background pairs against WCAG contrast thresholds. Users choose AA or AAA targets and receive exact ratios with pass or fail results. The generator keeps the chosen hue and saturation where possible, searching lighter or darker variants to meet the selected ratio. Accent colors may use analogous, complementary, or triadic hues and receive the same contrast check. A live interface preview shows the palette in context. Individual HEX values or a complete CSS custom-property block can be copied. Palette generation, contrast measurement, and CSS export run locally in the browser, and entered colors are not uploaded. The free plan allows unlimited palettes without an account or usage limit. Most tools continue working offline after the page loads. The report evaluates opaque sRGB contrast only and does not establish whole-product accessibility.

Leonardo is an open-source tool for creating, managing, and sharing accessible color systems for interface design and data visualization. Users can generate swatches from target contrast ratios or set target lightness, then adjust brightness, contrast, and saturation with adaptive themes. Sequential and diverging scales support data visualization. Accessibility tools can cycle through colorblind-safe palettes and compare color differences across color vision deficiency types, while charts and 3D models help evaluate themes. Themes and scales can be downloaded as SVG, and scales can also be exported as Tableau XML. Developer output includes parameters for @adobe/leonardo-contrast-colors, CSS custom properties, and design tokens. The related JavaScript package generates adaptive contrast-based colors and is installed with npm; its documentation includes vanilla JavaScript and React examples. The site also documents an MCP server for generating themes, checking contrast, converting colors, and creating palettes. The project is licensed under Apache V2 and has a free plan listed at free. One limitation is that generated contrast ratios can be slightly above requested values because RGB colors and color-space interpolation constrain exact results.