OtterDict is a Chinese-English dictionary and learning platform designed to make Chinese study accessible, practical, and connected. Its dictionary contains more than 121,000 entries, with pinyin, simplified and traditional characters, sourced example sentences, audio, and replayable stroke order. Users can search by Chinese characters, pinyin, or another language, and entries link directly to lessons that teach the vocabulary.

For structured learning, OtterDict offers an HSK 3.0 study path spanning six levels, with hundreds of lessons, vocabulary lists, and grammar points. The platform also includes grammar references, radicals, Hán-Việt readings, a pinyin table, review tools, notebooks, flashcards, and graded mock exams. Practical tools include handwriting recognition, image scanning, translation into about 130 languages, a reading room for pasted Chinese text, and a Chrome extension for looking up words while browsing. Some features, including speaking practice, are marked Pro, while core dictionary access is free. OtterDict also publishes articles on Chinese grammar, exams, and learning strategies, supporting learners from beginner level through advanced study.