Nano Immersive Translate

Bilingual on-device page translation. Insert translations per paragraph and chat with Gemini Nano LLM — offline, no keys, no tokens.

Read any web page in two languages, side by side, completely offline. Nano Immersive Translate keeps the original paragraph and inserts a translation directly underneath — like reading a bilingual book. Built entirely on Chrome's built-in AI: nothing ever leaves your machine. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ WHAT YOU GET ✦ Bilingual page reading Right-click any page → "Translate this page". Each paragraph gets a translation inserted right under it, with a soft accent border so you can scan original and translation in parallel. Works on news articles, Wikipedia, blogs, docs, anything. Click "Show original" on the same right-click menu to remove the translations and restore the page. ✦ Gemini Nano chat The toolbar icon → "Chat with Gemini Nano LLM" opens a full chat experience powered entirely by Chrome's on-device LLM: • Multiple tabs, each with its own session • Saved system-prompt presets — including a built-in "ESL Helper" that critiques your English writing • Light and dark themes • Streaming markdown responses • Export and Import — back up your tabs and prompts as a portable JSON file (so you can carry your history across reinstalls) ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ WHY YOU MIGHT WANT IT ✦ ESL learners and bilingual readers Read English news, papers, or docs while the translation streams in beneath each paragraph. Compare phrasing line-by-line. Use the built-in ESL Helper to polish your own writing. ✦ Privacy-conscious users The extension does not contact any server. No API keys, no accounts, no telemetry, no analytics, no remote configuration. Even the Markdown renderer in the chat page is bundled locally instead of fetched from a CDN. Your reading habits and chat content stay on your device. ✦ Travelers and offline workers Once Chrome has downloaded the small language pack for your target language (one-time, on first use), translation works fully offline — on a flight, on a subway, anywhere. ✦ Developers exploring Chrome's built-in AI This is a working reference for the Translator API, LanguageDetector API, and Gemini Nano Prompt API in a real Chrome extension. The full source ships with the package — no minified bundle. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ HOW IT WORKS ✦ Translation engine: Chrome's built-in Translator API. Source language is auto-detected per paragraph using Chrome's LanguageDetector API, so mixed-language pages translate correctly. ✦ Default target language: Simplified Chinese (zh-Hans). Switch any time from the toolbar popup — supported targets include Traditional Chinese, English, Japanese, Korean, Spanish, French, German, and any other pair Chrome's on-device translator supports. ✦ Chat engine: Chrome's Prompt API (Gemini Nano), running on-device. The first time you open the chat page on a machine without the model installed, the extension shows an in-chat setup guide with one-click links to the Chrome flags and components pages. ✦ The translation runs serially per session for reliability — Chrome's on-device translator can fail under heavy concurrent use, so paragraphs are translated one at a time with bounded retries on transient errors. A typical Wikipedia article finishes in a few seconds. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ REQUIREMENTS • Chrome 138 or newer, on desktop (Mac, Windows, or Linux). Mobile Chrome is not supported. • A few hundred MB of free disk for the on-device translation language packs. • ~2 GB of free disk for Gemini Nano (only required if you use the chat page). • Translator API works out of the box on most Chrome 138+ installs. Gemini Nano may require enabling two flags the first time — the chat page walks you through it step by step. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ PRIVACY The extension does not collect, store, or transmit any personal data. All translation and chat happens locally inside Chrome's built-in AI runtime. The only things stored on your device are: • Your target-language preference (in chrome.storage.sync) • Chat tabs, saved prompts, and theme (in localStorage on the chat page) You can export this data to a JSON file at any time, and removing the extension wipes all of it. There is no remote endpoint, no fallback API, no third-party analytics SDK. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ PERMISSIONS • "Read and change all your data on websites you visit" — required so the content script can read paragraphs from the page you're reading and insert translations beneath them. Used only when you explicitly trigger translation; never sent off-device. • Context menus — adds the right-click "Translate this page / Show original" item. • Storage — saves your target language and UI preferences. • Scripting — re-injects the content script into already-open tabs after a fresh install or update, so you don't have to refresh every existing tab. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ WHAT'S NEW IN 1.1.0 • Reader Mode — strip nav, ads, and sidebars before translating (right-click → Translate (Reader Mode)). • Faster on large pages — visible paragraphs translate first and stream in as they're ready. • Simpler menu — only "Show original" is shown when a page is translated. WHAT'S NEW IN 1.0.0 • Initial public release. • Bilingual whole-page translation via Chrome's Translator API. • Gemini Nano chat page with multi-tab sessions, system-prompt presets, theme toggle, and JSON export/import. • Built-in ESL Helper prompt for English writing feedback. • In-chat setup guide that walks new users through enabling Gemini Nano. Questions, bug reports, or feature requests are welcome — see the support contact in the privacy policy.