Lithos Talk is a live conversation translator for iPhone. People you talk with can join from a browser, with no app.
For language pairs downloaded to your iPhone, translation runs entirely on the phone with Apple's on-device speech recognition and translation, and no audio leaves the device. Otherwise, while a translation is running, audio from your microphone is streamed to Google's Gemini API to be transcribed and translated, and the translation is streamed back. Nothing is recorded or stored by the app or by our server. Lithos uses Google's paid Gemini API tier, whose terms exclude using that audio to improve Google's products; Google may keep it for a limited time to detect abuse.
If you add your own Gemini API key (Settings → Advanced), that audio goes to Google under your key and your Google project's terms. Your key is stored only in your iPhone's Keychain and is never sent to us.
There is no sign-up, email or password. The app creates a random account ID and secret and keeps them in your iCloud Keychain, so a new iPhone on the same Apple ID continues the same account. Our server stores the account ID, a hash of the secret, a short support code, your plan, and how many translation minutes were used each day and month. It also keeps a random device key created by Apple's App Attest for each phone, and the phone's name if iOS provides it.
Subscriptions and minute packs are processed by Apple. We receive Apple's signed record of the purchase (product, dates, renewal and refund status) tagged with your account ID, and never see your name, Apple ID or payment details. To limit repeated free allowances, the app may use Apple's DeviceCheck, which stores one bit per iPhone with Apple, not any identity.
To find and fix problems, the app sends: crash and performance reports from Apple's MetricKit (stack traces, device model, iOS version), and, for each translation session, counts and timings such as the number of turns, reconnects and how long translations took. These are stored without any account or device ID and deleted after 30 days (session counts after 90 days). If you tap Send diagnostics in Settings, the app sends a technical log of the last 15 minutes with your support code; it never includes what anyone said or the translations. None of this contains audio, transcripts or translations.
If you join from a link or QR code, your audio goes to the host's phone, which translates it. The connection is encrypted end to end: directly between the two devices when possible, otherwise through Cloudflare's relay or our server, which only ever forward encrypted data. Calls started from the Lithos Talk app carry their encryption key in the part of the link after the #, which browsers never send to any server. Nothing is recorded or kept, no conversation text is shown or sent to your browser, and the join code expires after the conversation.
Conversations appear on screen while the app is open and are not saved. Your language settings and recent calls (join codes only) are stored on the phone.
No ads, third-party analytics or tracking, and no data is sold or shared for marketing.
Email hello@lithos.community with your support code (Settings → Plan), and your account, device records, usage history and diagnostics will be deleted.