Attach: tmux & SSH tunnel

Attach is a tmux client for Android that connects over SSH.

Your shell runs on the server inside tmux, not on your phone. Attach speaks tmux

control mode (tmux -CC), so it drives that session as a real app: windows appear as

tabs, split panes are laid out and rendered natively, and scrollback belongs to the

pane rather than to a stream of escape codes.

Because the session lives on the server, leaving does not end it. Switch apps, lose

signal, or close Attach entirely — the shell keeps running, and reattaching puts you

back exactly where you were, with whatever was still running still running. Attached

sessions are held open by a foreground service while you are elsewhere, and a lost

connection can reattach on its own.

SSH PORT FORWARDING

Local (-L), remote (-R) and dynamic (-D / SOCKS) forwarding, run from the same app and

the same saved connections. Tunnels stay up in the background, and one connection can

depend on another — reach a private host through a jump server and Attach brings the

chain up in the right order. Optional auto-reconnect restores a tunnel after a network

drop.

THE TERMINAL

A VT100 terminal emulator with scrollback, text selection, adjustable fonts and colour

schemes, and a customisable toolbar for the keys a soft keyboard does not have — Esc,

Tab, Ctrl, arrows. CJK input and hardware keyboards are supported.

CREDENTIALS STAY ON YOUR DEVICE

Passwords and private keys are encrypted at rest with a key held in the Android

Keystore, hardware-backed where the device supports it. They are never written in

plaintext, never uploaded, and can optionally be locked behind your fingerprint or

screen lock. Authenticate with a password, a public key, or both. ed25519, ECDSA and

RSA keys are supported, and keys can be imported from files on your device.

HOST KEYS ARE CHECKED

Server host keys are pinned on first connection. If a pinned key ever changes, Attach

stops and shows you both fingerprints — it will not silently accept the new one.

CONNECT THROUGH A PROXY

Connections can be routed through a SOCKS5 proxy. Host key verification still applies

end to end.

WHAT YOU NEED

An SSH server you already have, with tmux installed on it for the terminal features.

Attach does not provide a server, and it has no user accounts or sign-in of any kind.

PRIVACY

Your connection details, credentials and terminal contents stay on your device and are

never sent anywhere. The app has no analytics or behavioural tracking. It does show

banner ads, which are non-personalised by default; you can change that in Settings,

along with crash reporting. Full details: https://attach-a2a68.web.app/privacy