Most "mobile SSH" is a second, smaller app that shares a logo with the real one. Voltius for Android is the opposite bet: it's the same app. Same terminal, same hosts and folders, same SFTP browser, the same Docker, metrics, processes and Proxmox panels for your SSH hosts — compiled to a signed arm64 APK and running on your phone.
One codebase, two very different machines
Voltius is a Tauri app: a web frontend over a Rust core. Tauri's mobile support means the frontend mostly comes along for free — but "mostly" is where all the work is. A desktop SSH client makes assumptions a phone doesn't honor, and each one had to be found and gated to the right platform.
The native keychain was the first blocker and the most important one: credentials have to live in real secure storage, which means an encrypted store whose master key lives in the hardware-backed Android Keystore on the phone, and the system keychain (macOS Keychain, Windows Credential Manager, Secret Service on Linux) on the desktops — the same keychain abstraction, four backends underneath. Downloads were the second: a phone doesn't have a free-roaming filesystem, so SFTP downloads route through Android's Storage Access Framework and land in a folder you grant access to, while the desktop keeps its ordinary path-based downloads. A pile of these helpers are now gated android-only or desktop-only so each platform compiles clean and behaves like it belongs there.
A terminal you can drive with your thumbs
A terminal assumes a keyboard and a mouse. A phone has neither, and the naive port — a tiny xterm you pinch-zoom and fat-finger — is miserable. So Voltius has a gesture layer built specifically for the compact terminal.
- Swipe to scroll the scrollback, instead of hunting for a scrollbar that doesn't belong on a touchscreen.
- Long-press to select text, with a floating copy/paste toolbar that appears at the selection — and tapping the toolbar no longer clears the very selection you're acting on, which is the bug that makes most mobile terminals' copy useless.
- Paste into blank area so you don't have to aim at the cursor.
- Double-tap for Tab, because shell completion is the one key you reach for constantly and the on-screen keyboard buries it.
- Drag the selection handles to grow or shrink a selection character by character, across lines.
- Pinch to resize the terminal text, independently of the rest of the app.
Underneath, the gesture geometry and selection math are pure functions with their own tests, separate from the touch plumbing — so "did the swipe register as a scroll or a tap" is something we can assert in CI rather than discover on a device. We suppress the synthetic touchend after a swipe-scroll so it doesn't fire a stray tap, and the toolbar closes itself on teardown instead of leaking onto the next session.
Same security model, smaller screen
The point of sharing the codebase isn't tidiness — it's that the security and feature guarantees come along unchanged. Credentials sit in the OS keystore. The end-to-end encrypted sync that carries your hosts between desktops carries them to your phone too. There's no reduced "mobile" backend cutting corners; it's the Rust core you already trust, on a fourth target.
Voltius for Android ships as a signed arm64 APK. Like the rest of Voltius, it's open source — including the platform gates, if you want to see how a desktop app earns its place on a phone.