AI Translator (Offline)
Translate English to 19 languages instantly — free, no API key, and nothing leaves your device. The Opus-MT models run entirely in your browser using Transformers.js.
How It Works
Paste your English text
Drop in any English text — up to 5,000 characters. Emails, articles, messages. Nothing is sent anywhere.
Pick a target language
Choose from 19 widely spoken languages. Each language uses a dedicated bilingual Opus-MT model that loads on first use.
Model translates in-browser
Helsinki-NLP Opus-MT runs inside a Web Worker using WebAssembly. Long text is split into sentence-aware chunks.
Copy or download
Copy the translated text to your clipboard or download it as a .txt file — all in the browser, no server involved.
Why Use an Offline AI Translator?
Cloud translators such as Google Translate, DeepL, and Microsoft Translator transmit every word you type to their servers. For confidential emails, internal documents, customer messages, or any text covered by GDPR, HIPAA, or your employer's data-handling policy, that round-trip is a real risk. An on-device translator removes the round-trip entirely — your text never leaves the browser tab.
Supported Languages
This release supports English as the source language and 19 target languages selected for global coverage. Each language uses a dedicated bilingual Helsinki-NLP Opus-MT model (one ~75 MB download per language, the first time you select it):
| Region | Languages |
|---|---|
| Western Europe | Spanish, French, German, Italian, Dutch |
| Northern Europe | Swedish, Danish, Finnish |
| Eastern Europe | Russian, Czech, Hungarian, Romanian, Ukrainian |
| Asia | Japanese, Chinese, Hindi, Vietnamese, Indonesian |
| Middle East | Arabic |
How to Use the Offline AI Translator
- Paste your English text into the input area — up to 5,000 characters.
- Select a target language from the dropdown.
- Click Translate. On first use you'll be asked to confirm a one-time ~75 MB model download.
- Read the translated text in the output panel.
- Click Copy to send it to your clipboard, or Download .txt to save it.
- Click Reset to start over with new text.
Key Features
- Runs 100% in your browser — no data ever leaves your device; nothing is uploaded to a server.
- Free with no sign-up — no API key, no usage limits, no account, no watermarks.
- 19 target languages — broad global coverage via dedicated bilingual Opus-MT models (one ~75 MB download per language, on first use).
- Automatic sentence-aware chunking — long inputs are split on sentence boundaries (., !, ?) so each chunk fits the model's context window without breaking grammar mid-sentence.
- Offline after first load — each model downloads once and is cached in your browser's IndexedDB storage.
- Copy or download — get your result on the clipboard or as a plain-text file in one click.
- Open-source models — Helsinki-NLP Opus-MT is freely available under the Apache 2.0 license.
Best Use Cases
- Confidential business email — translate a draft before sending without exposing the contents to a cloud provider.
- Travel phrases — generate phrases offline once you've loaded the model, even with no signal.
- Internal documentation — translate snippets of internal docs without breaching data-handling policies.
- Regulated industries — legal, medical, or financial drafts where data residency or HIPAA / GDPR compliance forbids third-party processing.
- Education — students and language learners can experiment without consuming any API quota.
Accuracy Notes
A 75 MB neural translator is dramatically smaller than the multi-billion-parameter models that power Google Translate and DeepL. Expect strong results on short, plain text and slightly weaker results on long, idiomatic, or highly technical passages. For high-stakes translations always have a fluent speaker review the output. The trade-off is privacy: nothing you type is ever transmitted off your device.
Frequently Asked Questions
Is my text uploaded to your servers?
No. Your text never leaves your device. Translation runs entirely inside your browser using Transformers.js and an open-source Opus-MT translation model. Nothing is sent to or stored on any server.
Why is the first translation slow?
The first time you use a given target language, your browser downloads the bilingual AI model for that language (~75 MB) and saves it to local storage (IndexedDB). After that one-time download the model loads instantly, and the tool works even offline. Switching to a different target language triggers another one-time download for the new language.
Which AI model is used?
The tool uses Helsinki-NLP Opus-MT — a family of bilingual sequence-to-sequence neural machine translation models trained on the OPUS parallel corpus. One bilingual model (Xenova/opus-mt-en-XX) is loaded per target language and runs as a quantized ONNX model via Transformers.js entirely on your device. The models are open source under the Apache 2.0 license.
Which languages are supported?
This release supports English to 19 target languages: Spanish, French, German, Italian, Dutch, Russian, Japanese, Chinese, Arabic, Hindi, Swedish, Danish, Finnish, Czech, Hungarian, Romanian, Ukrainian, Vietnamese, and Indonesian. Each language uses its own bilingual Opus-MT model. Contact us if you need an additional language.
What about translating from another language into English?
The reverse direction (any-language → English) requires a different Opus-MT model and is on the roadmap. For now this tool covers English as the source language.
How does on-device translation compare to Google Translate or DeepL?
On-device translation is private and free with no rate limits, but a 75 MB browser model is smaller than the multi-billion-parameter cloud models behind Google Translate and DeepL. For short, plain text the quality is good; for long idiomatic or technical passages cloud models are still stronger. Choose on-device when privacy matters most.
Does this work offline?
Yes. After a target language’s model is downloaded on your first use, it is saved to your browser’s local storage. You can then translate into that language without an internet connection.
What is the maximum text length?
The tool accepts up to 5,000 characters. For longer inputs the translator automatically splits the text on sentence boundaries (., !, ?) so each chunk fits the model’s ~512-token context window without breaking grammar mid-sentence.
Privacy & Security