Canto Toolbox

Hover Chinese text for Mandarin and Cantonese definitions with audio, radical breakdown, and spaced-repetition flashcards.

Canto Toolbox shows Chinese word definitions when you hover over characters on any webpage. Definitions appear in both Mandarin (with Pinyin) and Cantonese (with Jyutping). For each character, a radical breakdown is shown when available: radical, structure (IDS decomposition), and etymology hints (pictographic, ideographic, or pictophonetic). You can select multiple characters to look up whole phrases. Chinese inside pictures works too: hover a screenshot, comic panel, menu or sign - or pause a video on a subtitle — click the badge in its corner, and the text it holds becomes hoverable in place. Recognition runs on your own machine, with nothing uploaded. The extension works offline using local dictionary data, tracks your most frequently looked-up words, supports simplified and traditional characters, and follows your system theme (including dark mode). Useful for reading Chinese online, whether you're learning Mandarin, Cantonese, or both.