Episteme

OSS Edition

Privacy Policy for Episteme OSS

Last updated: May 22, 2026

This Privacy Policy explains how information is handled in the open-source editions of Episteme ("Episteme OSS", "we", "us", or "our"). It covers the OSS build distributed through GitHub, F-Droid, and similar open-source channels, including the OSS Offline build where applicable.

Summary: Episteme OSS is local-first and does not include Episteme account services, Google Sign-In, Google Drive cloud sync, Firebase-backed account sync, Google Play Billing, Episteme credits, or Episteme server-backed AI. The online OSS build can still access network features you choose, such as OPDS catalogs, font downloads, external links, and bring-your-own-key AI providers. The OSS Offline build is intended to avoid network-backed features.

1. Information Stored Locally

Episteme OSS stores app data on your device so the reader can function. This may include:

  • Imported books, documents, comics, and text files.
  • Reading progress, bookmarks, annotations, highlights, shelves, tags, and local library metadata.
  • Reader settings, themes, fonts, text-to-speech preferences, language settings, and file handling preferences.
  • Local folder sync state and file metadata for folders you choose to connect.
  • Bring-your-own-key AI settings and provider keys, stored locally and protected with platform secure storage where available.
  • Local logs or diagnostics generated by the app, unless you choose to share them with us.

This local data remains under your control on your device. We do not operate an Episteme account backend for OSS builds that receives your library, reading progress, or documents.

2. Information We Do Not Collect in OSS

Episteme OSS does not include the standard edition's Google account cloud stack. In the OSS build, we do not collect or process:

  • Google Sign-In profile data for an Episteme account.
  • Episteme Pro purchase tokens or Episteme credit purchases.
  • Firebase account records, Firestore cloud sync metadata, or Firebase device management records.
  • Google Drive appDataFolder cloud sync files through an Episteme account flow.
  • Server-backed Episteme AI or cloud TTS requests paid for with Episteme credits.

3. Optional Network Features in OSS

The online OSS build may include network features that run only when you use them. Depending on your settings and build, these can include:

  • OPDS catalogs: If you add or browse an OPDS catalog, your device connects to that catalog and sends the requests needed to browse or download content. The catalog provider's privacy practices apply.
  • Google Fonts or other font downloads: If you download fonts, your device contacts the font provider to fetch the selected files.
  • External links and lookups: If you open an external website, dictionary, search, or lookup, that provider receives the request from your device.
  • Feedback you send manually: If you email us, open an issue, or attach logs/screenshots, we receive only what you choose to send.

The OSS Offline build is designed to disable network-backed features and remove network permissions where supported by the platform. If you install a modified build, its behavior may differ from the official OSS builds.

4. Bring Your Own Key AI Features

Episteme OSS may let you add your own API key for AI, cloud text-to-speech, summarization, recap, dictionary, or similar features. When you use bring-your-own-key features:

  • Your API key is stored locally on your device where possible, using platform secure storage when available.
  • Your key is not sent to Episteme servers by the official OSS build.
  • Requests are sent from your device to the provider you choose, such as the AI API endpoint configured in the app.
  • The provider may receive selected text, page images, excerpts, prompts, generated context, outputs, device network information, and usage metadata needed to process the request.
  • The provider's terms, privacy policy, retention, training, logging, pricing, and abuse monitoring rules apply to those requests.

You are responsible for protecting your API keys, monitoring usage, understanding provider data practices, and complying with provider terms.

5. How We Use Information

For the official OSS builds, we use information only to provide the local app features you run on your device or to respond to information you voluntarily send us. We do not sell your personal information. We do not use your documents to train our own AI models.

6. Retention and Deletion

  • Local app data remains on your device until you delete it, clear app storage, remove connected folders, delete saved keys, or uninstall the app.
  • Data sent to third-party OPDS catalogs, font providers, external websites, or AI providers is governed by those providers.
  • Emails, issues, feedback, screenshots, and logs you send us may be kept as long as needed to respond, debug, maintain records, and improve the project.

7. Security

Episteme OSS uses platform storage and security features where available. For bring-your-own-key settings, the app attempts to protect saved keys using platform secure storage. No software can guarantee perfect security. Keep your device, backups, and provider accounts secure, and revoke keys if you believe they were exposed.

8. Children

Episteme OSS is not directed to children under 13. If a child uses the app, a parent or guardian is responsible for the device, content, network providers, and any API keys configured in the app.

9. Your Choices

  • Use the OSS Offline build if you want the most restrictive network behavior.
  • Do not add OPDS catalogs, external lookups, downloaded fonts, or AI provider keys if you do not want those network requests.
  • Delete local library data, annotations, settings, logs, and saved keys from the app or operating system storage controls.
  • Contact third-party providers directly for data requests about information sent to them.

10. Changes to This Policy

We may update this Privacy Policy as the OSS build changes. The latest version will be posted on this page with an updated date.

11. Contact

Questions can be sent to epistemereader@gmail.com or raised through the project issue tracker.