Messaging · calls · rooms
Messages, voice and video calls, photos and videos, voice rooms, polls and events — all end-to-end encrypted, with an AI that runs on your phone instead of in someone's data centre. No account. No phone number. No ads.
Free. Open it, pick a name, create a room and share its invite code or link — that's the whole sign-up. The desktop apps join the same encrypted rooms and the same calls as the phones — encrypted voice and video calls from your desk; voice-note recording and stickers are still phone-only. Install notes for every platform below.
What Tern does
Create a room, share its code, talk. Per-member encryption with the IETF's MLS standard, real revocation when someone leaves, and a relay that only ever carries sealed bytes.
One-to-one and group calls up to thirty people. Every frame is encrypted on your phone; the call server forwards packets it cannot decode. Switch to video mid-call, add someone, pin a tile, picture-in-picture.
A Calls tab on every phone. A call that came while your phone was off still shows when you're back — history syncs sealed, like messages.
A busy room opens as a grid: channels, voice rooms showing who's inside right now, the open poll's tally, the next gathering's RSVPs, your shared media.
Hop in, hop out — nobody's phone rings. Presence is a heartbeat that never touches storage: no record of who was in a room exists on any server.
Photos stripped of location data on the device, videos transcoded on the phone, voice notes with review-before-send, stickers you cut out yourself, view-once photos, disappearing messages.
Ask the room and watch the tally move. Plan a gathering with RSVPs. Post a 24-hour update that deletes itself everywhere.
Catch Me Up summaries in eight languages, reply suggestions, ask-your-chat answers, message search — computed by a model on the phone itself. Always labelled, never sent anywhere.
Your identity is a key your phone made. Invite people from contacts without uploading contacts. There is no directory to breach and no number to leak.
Why it's different
Every big messenger is bolting cloud AI onto private chats — your words travel to their models. Tern's summaries, suggestions and search never leave the phone. Not "we promise not to look": we can't.
Your history lives on your devices and syncs through a relay that forwards sealed envelopes. Offline works. The relay going down loses nothing.
No feeds, no streaks, no red badges engineered for anxiety, no autoplay. "You're all caught up" is a feature. Built to the EU's rules for humane software before they were enforced.
Type anything. The right side is what a relay, a network, or anyone in between sees. (This demo runs entirely in your browser; nothing is sent.)
Install notes
1Tap the iPhone button above. It opens TestFlight — install it from the App Store if asked, then Tern. The App Store listing is in review; TestFlight installs the same 1.0 app today.
2Updates arrive automatically: Tern checks each time you open it and, when a new build is out, shows one "Update now" that opens TestFlight (or the App Store).
1Download the APK with Chrome, then open it from Chrome's Downloads. On Xiaomi / Redmi / POCO the built-in Mi Browser and the "GetApps" prompt can block a direct install; Chrome does not.
2Allow "Install unknown apps" for Chrome when asked. Oppo, Realme, Vivo, Infinix and Tecno sometimes hide the switch: Settings → Apps → Chrome → Install unknown apps → Allow, then open the file again.
3If Play Protect says "Unknown app blocked": More details → Install anyway. Xiaomi's own scan: Continue / Install anyway.
4Phones without Google services (Huawei and others) install the same way; Tern uses no Google services at all.
5New versions install from inside Tern: it downloads the update itself, checks it, and asks you to install with one tap. Android asks once to allow "Install unknown apps" for Tern. Everything stays where it was.
1Unzip, drag Tern to Applications.
2First open: right-click → Open → Open. The app isn't notarized yet, so macOS asks once.
3New versions: the app tells you on launch and opens the download; drag the new Tern over the old one.
4Had the earlier Mac app? This one is new (same features as Windows) and starts fresh — rejoin your rooms with their invite codes.
1Unzip anywhere, run Tern.exe.
2If SmartScreen appears: More info → Run anyway. The app isn't code-signed yet.
3New versions: the app tells you on launch and opens the download; unzip over the old one.
Questions
Open Tern, enter a name, tap Create a room. You're in it immediately. Share the room's invite code or link with the people you want — that is how everyone else gets in. Tern has no public directory and no "people you may know": rooms are made of people who already know each other.
No. Your identity is a cryptographic key your device generates. There is nothing to register, verify, or recover from a server — which is also why you should keep the app installed on a device you keep.
No, and not by policy — by construction. Messages are sealed on your device with the room's group key; the relay stores envelopes it cannot open. Calls are encrypted frame by frame on your phone; the call server forwards packets it cannot decode. We publish a test that proves the call server sees only ciphertext.
Catch Me Up summaries, reply suggestions, search and voice-note transcription run on the phone with small models downloaded once. Nothing is sent to a server, and everything AI-generated is labelled as such.
No feed, no ranking, no algorithmic timeline. Rooms are chronological. When the messages end, you're caught up.
Yes.