Duo Translator

Duo Translator is a free, open-source browser extension positioned as an all-in-one AI translation and writing assistant. It supports webpage translation, selected text translation, writing enhancement, and more, displaying translations side by side with the original. Built-in translation services include Microsoft, Google, Yandex and DeepL. AI services support OpenAI, DeepSeek, Gemini, OpenRouter, Claude, Ollama, and custom AI providers. Additional features include looking up words by hovering over them, downloading subtitles and splitting them into sentences with AI, and opening a dedicated AI workbench to edit long-form text and review the output more easily. Duo Translator works on Chromium-based browsers like Chrome and Edge, and on Firefox. It syncs preferences through a single configuration file inside the hidden application data folder of your Google Drive, containing translation and AI provider settings, translation and highlight styles, keyboard shortcuts, and per-site rules and lists.