Privacy notice
Last updated: September 1, 2026
OnlyTranslate is a free, open-source browser translation extension. This notice explains what information is stored in your browser, when text is sent to a third-party translation service, and how you can manage that data.
No OnlyTranslate account required
OnlyTranslate does not provide a project-operated account system and does not require sign-in or a subscription. The project does not collect routine usage analytics, browsing history, translation history, or imported ebooks through the extension.
Optional uninstall feedback
When supported by the browser, uninstalling OnlyTranslate may open a feedback page on the project website. You can close the page without responding, or voluntarily select options describing the main reason for uninstalling and any first-use obstacle. Some reasons display a short follow-up question, and “Other” requires an explanation.
If you submit the form, the project stores the selected categories, details you choose to enter, optional service and model, extension version, interface language, and submission time. The feedback system does not persist IP addresses, request headers, page URLs, translation content, or a user identifier. Data is used only by project maintainers to aggregate product issues and is retained for no more than 90 days. Fixed-option responses from older extension versions may remain in a field-filtered dedicated Caddy log.
Optional private feedback
The extension settings page and the project website feedback page can both send feedback to the same private endpoint. The feedback message, category, interface or website language, and submission time are stored with the submission; extension submissions also store the extension version. The page URL and a contact email are off by default and are included only when you explicitly enable the corresponding option. When you follow a private feedback link from a product update, that article URL is shown and selected in advance, and you can deselect it before submitting. The website cannot read local extension diagnostics. Only the extension settings page lets you optionally attach recent translation diagnostics. Diagnostics contain only session text size, request and cache counts, queue and API timings, time to first result and completion, service, a known model or custom marker, retries, and error types. They do not contain source text, translations, API keys, custom model names, or endpoints. An explicitly submitted page URL retains its query string and has its # fragment removed; query parameters may contain tokens or personal information, so review them before submitting. A contact email and follow-up consent you voluntarily provide are used only by project maintainers to follow up on that feedback and are retained with it for no more than 90 days. Private feedback does not persist IP addresses or request headers.
Data stored in your browser
The following data is stored in your current browser profile:
- translation service and interface settings;
- translation results and video subtitle cache;
- imported or saved original EPUB/PDF files;
- ebook library, reading progress, and location bookmarks;
- the optional PDF layout model you explicitly download;
- third-party service parameters you choose to configure.
Uninstalling the extension, clearing extension data, or removing a book may delete the corresponding local data. OnlyTranslate does not currently provide cloud sync or remote backup.
Online translation services
When you select Microsoft Translator, Google Translate, DeepL, OpenAI, DeepSeek, Gemini, Claude, or another online endpoint, the webpage text, subtitles, or text extracted from an EPUB/PDF for translation is sent to that provider.
Those requests are governed by the selected provider’s privacy policy, account rules, and data-processing terms. OnlyTranslate does not manage the provider’s accounts, quotas, billing, or data-retention policies.
When supported by the current browser and language pair, Chrome built-in translation can process text locally. Availability depends on the Chrome version, local model state, and language pair.
Read-aloud and online voice
System voice is handled by a speech engine provided by Chrome, Edge, or the operating system. When you select Edge online voice and explicitly click Read aloud or Preview, the corresponding source text, translation, or preview text is sent directly over an encrypted connection to the Microsoft speech synthesis service to generate and return audio. Servers operated by the OnlyTranslate project do not receive or retain this text or audio.
Edge online voice requests are governed by the Microsoft Privacy Statement and its data-processing terms. You can switch back to System voice (recommended) in OnlyTranslate's voice settings.
API keys and service configuration
API keys and service settings you enter are stored in browser extension storage and are used to send requests to the selected service. The OnlyTranslate project does not receive or host these credentials.
Do not save private API keys on a public device. When available, use the provider’s security controls to limit key permissions and spending.
EPUB and PDF data
Imported or saved original EPUB/PDF files, library information, reading progress, and bookmarks remain in the current browser. They are not uploaded to the OnlyTranslate project, and the original files are not sent to translation providers. When translation begins, extracted text that needs translation is sent to the provider you selected. Original-only mode does not send text for translation in advance.
PDF uses basic layout analysis by default. You can explicitly download an optional layout model of about 23 MB; it stays in extension-private storage and runs locally. The original PDF is not sent to the model host, and you can remove the model at any time.
Cache
Translation results and video subtitles may be cached locally to reduce repeated requests and waiting time. You can clear the cache from the More menu in the top-right of the OnlyTranslate popup.
Open source and inspection
OnlyTranslate is open source under GNU GPL v3.0. The source code, release history, and issue tracker are available on GitHub.
The project continues development from FluentRead and retains credit for the original project and its contributors.
Contact and feedback
For questions about this notice, uninstall feedback, data flow, or a specific feature, contact the maintainers through GitHub Issues.