The computer half of Tetra for Android: Photos, Files, Notes,
Calendar, Timer, Maps*, Contacts, Phone and Data on Linux, in sync with your phone and tablet over your own Wi-Fi.
Faces, documents and search labels are analysed on this computer.
0.6.0 Beta 32 (what's new). A beta: keep
your own backups. Screenshots use invented sample data.
What Tetra does for you
- Files to and from your phone in a second. Send to phone in Files or from the tray, and Send to computer in
the phone's share menu. Over your own Wi-Fi: no cable, no cloud. They land in
From phone and From computer.
- Call from your computer. Click a number in Contacts and your phone dials it; a call bubble answers, holds, mutes,
hangs up and moves the sound to the phone's loudspeaker, and the phone's Recents and Recordings are here too.
- Maps of any country, made here. Settings › Maps › Add a map: pick a country or a region, and this computer makes
its map, search and routes from OpenStreetMap, then sync sends them to your phone and tablet. Routes cross borders at
the real crossings, with directions in your language. The AppImage carries the Java and Python the builder needs.
- In your language, with a guide. All 24 official languages of the EU. A guide beside the page, on first start and
in Settings › Guide, shows where to click and why.
- Your data plan, watched. The phone's and the tablet's usage beside this computer's; the phone notifies you at 50 %,
80 % and 100 % of your plan, or at any steps you choose.
- Calendar and timers, with AI. Your calendars and timers are plain files in
~/Tetra/Files, and Tetra comes with
skills for them (Share with Claude). Ask Claude, ChatGPT or any assistant that can use your computer to import a
timetable, plan your week or set a timer; the result reaches your phone with the next sync.
- Notes and lists, organised. Notes and shopping lists with tags, the same on the phone and here. Each note is a
plain file in your own Tetra folder.
- Photos that know who and where. Bring your Google Photos over (Takeout import, with their dates), then tags, live
photos, and People and Documents collections from face recognition that runs on this computer. Find photos by place*.
- Keep the internal SSD light. Pair an external drive with Tetra and it backs everything up automatically, or moves
older photos onto it so the computer's own disk stays as empty as possible.
- More than one copy, no subscription. Tetra shows how many places hold each file, the phone, the tablet, the
computer or a USB drive, and what still lives in only one. Your own backups, with no cloud plan to pay for.
- Maps that work offline. Search, save places, lists and trips, and plan routes by car, on foot or by bike.
* Finding photos by place covers Greece only for now.
The applets
Also here: Devices, to pair a phone or tablet by QR code with rules per device (send, both ways, or Move);
storage drives, a USB disk as a verified backup or as storage that still shows in the library; and a Trash that
waits 30 days, then 30 more in a purgatory, before anything is really gone. Each applet's screenshots, phone, tablet
and computer apart, are on the Tetra page.
Fast
Each page was measured on a copy of a real library (16 619 photos): how long until it stops changing, and the longest
moment the window could not answer. Files, Notes, Calendar, Timer, Maps, Contacts, Data, Devices and Settings were
already quick (2–160 ms). Two froze the window, and no longer do:
| Page | before | now | what changed |
|---|
| Photos (opened again) | 741 ms, the window busy 599 ms | 71 ms, never busy | a period's photos are made only within two screens of the view, so any size of library opens the same |
| Phone | 510–545 ms, busy 288–293 ms | 47–76 ms, never busy | sixty recent calls at first, more as the list's end nears |
On the phone, the same week, Contacts went from 3.3 s to 0.19 s and the Phone from 2.3–2.8 s to 0.25 s: see
Tetra for Android.
Sync
Pair once by QR code from Devices; each file is checked by SHA-256 on arrival. A trusted device is known by its public-key fingerprint, not its IP
address, so it is found again after a network change. Every rule and its reason is in SYNC_PLAN.md.
Install
On Debian, Ubuntu or Mint:
sudo apt install ./local-drive-desktop_0.6.0-beta.32_amd64.deb
Or make the AppImage executable and run it (chmod +x Tetra-0.6.0-beta.32.AppImage); it needs nothing else,
not even libfuse2. Tetra keeps running in the tray when its window is closed, so phones can sync at any time.
Then install Tetra for Android on your phone or tablet and pair it
from Devices.
Build
The app is in desktop/ (Electron, React, TypeScript).
cd desktop
npm ci
npm test
npm run dist # release/*.deb and *.AppImage
Documentation
| Document | Purpose |
|---|
| desktop/README.md | The desktop app's code map, folders and development commands |
| SYNC_PLAN.md | Sync design and every rule's reason (the same file in both repos) |
| HANDOFF.md | Where work stands, newest first |
Licence
Tetra is free software under the GNU GPL 3.0, and will stay free.
History: the C++/Qt "Local Drive"
Until September 2026 this repository held a C++/Qt desktop app with a browser-page interface. It was replaced by
the Electron app in desktop/ and removed on 26 September 2026. Its code, plans and safety specification are in the
history, at commit 1b71025.
