RTerm — a fast, SSH-first Android terminal

RTerm is a lean, SSH-only Android terminal built around a Rust core. It exists to fix the exact things that make SSH-over-Termux painful: no real SHIFT key, key combos that don't encode correctly, a renderer that chokes on vim/tmux, and sessions that die the moment you switch apps.

⬇️ Download

RTerm-1.3.0.apk — ~12.3 MB · arm64-v8a · Android 7.0+

Sideload only, no Play Store. All releases: Releases · install steps

Live SSH session — full VT100 grid	Configurable key bar with sticky modifiers

Why RTerm

Termux is great — but for SSH it gets in the way. RTerm is SSH-only and fixes the friction.

	What you get
⌨️	Modifier keys that work — a real SHIFT key (Termux/Rin have none). Sticky one-shot & lock modifiers. Shift+Tab actually sends ESC [ Z; Ctrl/Alt combos encoded correctly in the Rust core.
🖥️	Full-screen apps — a real VT100 grid (vendored Termux engine) so vim, tmux, htop and ANSI colors render properly, not a line-buffer that strips escape codes.
⚡	Low latency — TCP_NODELAY, keys firing on finger-down, protocol keepalives that hold NAT paths open. Tuned for sub-second echo.
🗂️	Multi-session tabs — several SSH sessions at once, each with its own identity color and sticky modifiers.
🔁	Stays alive & reconnects — a foreground service (with notification) keeps the session alive when you leave the app; auto-reconnect with backoff plus a manual retry button.
🔐	Host-key pinning — trust-on-first-use with a hard-fail on mismatch (MITM protection).
📁	SFTP file browser — browse remote dirs, tap to download, upload from the phone, via Android's Storage Access Framework (no storage permission).
🔀	Port forwarding — -L local forwards and a SOCKS5 dynamic proxy over the SSH channel. Tunnel to your server's internal services from the phone browser.
🤖	Macros & automation — script routines (send / wait / wait-for-output / if-contains-goto / copy), auto-run on connect, and daily scheduled headless runs.
🎛️	Configurable key bar — add/remove keys & rows, long-press symbol popups, hide/show from the ▶ menu, and native sequence keys like ctrl+b q (tmux prefix).
🎨	Themes & fonts — 8 color schemes (Dracula, Solarized, Gruvbox, Nord, …), bundled monospace fonts, your own uploaded fonts, and a zoom dialog — all applied live.
📦	Config backup — export connections, macros, key bar & forwards. Secrets stripped by default; opt-in passphrase encryption (PBKDF2 → AES-256-GCM).

Security & privacy

A terminal app handles your most sensitive credentials. RTerm is built to respect that.

• Minimal permissions. Only INTERNET plus foreground-service / notification / boot. No storage, contacts, location, camera or microphone.
• Secrets encrypted at rest. Passwords, inline keys & passphrases are wrapped with AES-256-GCM under a hardware-backed Android Keystore key that never leaves the device.
• Host-key verification. First contact pins the fingerprint; any later mismatch hard-fails the connection.
• Backups disabled. android:allowBackup="false" — app data can't be pulled via adb backup.
• Tight component surface. All services & receivers are non-exported; the Quick-Settings tile is system-protected (BIND_QUICK_SETTINGS_TILE).
• On-device keys never leave. SSH keys generated in the app are excluded from config export.
• Open source. The complete source is in this repository — audit it yourself.

These properties describe the source. The currently published APK is a debug build, which relaxes the on-device protections — see the install warning.

Install

1. Download RTerm-1.3.0.apk.
2. Copy it to your phone (or adb install RTerm-1.3.0.apk).
3. On the phone: Settings → Apps → Special access → Install unknown apps, allow your file manager / browser to install.
4. Tap the APK to install, then open RTerm.
5. Add a connection (host / port / user + password or key), connect, and try SHIFT then TAB.

Verify your download with sha256sum RTerm-1.3.0.apk:

50a9bbfca1176ca110a7914b74bd6d8c0df92e1cdcb3c9809c42522e2b2ace16  RTerm-1.3.0.apk

Warning

The current release artifact is a debug build. Two consequences worth knowing before you put real credentials in it:

• It is signed with a local debug key, so Android warns it's from an "unknown developer", and it carries android:debuggable="true". On a debuggable app anyone with USB/ADB access to the unlocked device can run-as the app to read its private data directory, or attach a debugger to the running process — which reaches secrets after they've been decrypted. The at-rest encryption below still holds; this weakens the on-device threat model.
• It reports versionCode 9 / 1.2.2 internally (it was built before the version bump), even though it contains the 1.3.0 code. Android will display it as 1.2.2 and will not treat it as an upgrade over a real 1.2.2 install.

A release-signed, non-debuggable, correctly-versioned build will replace it. Until then, prefer building from source if either point matters to you.

Specifications

Version	1.3.0 (source: versionCode 10 — see the build note above)
Application ID	ovh.binary.rterm
Min / target Android	7.0 (API 24) / 14 (API 34)
Architecture	arm64-v8a (modern phones)
APK size	~12.3 MB
SSH engine	russh (Rust)
Terminal engine	vendored Termux (Apache-2.0)
UI	Kotlin + Jetpack Compose

Build from source

Prerequisites: JDK 17+, Rust + cargo-ndk, Android SDK (platform 34, build-tools 34), NDK r26.

# 1. Rust native library (arm64 .so)
cd rterm
export ANDROID_NDK_HOME=$ANDROID_HOME/ndk/26.3.11579264
cargo ndk -t arm64-v8a -o android/app/src/main/jniLibs \
      build -p rterm-core --release --features android

# 2. APK
cd android
echo "sdk.dir=$ANDROID_HOME" > local.properties
./gradlew :app:assembleDebug
# -> app/build/outputs/apk/debug/app-debug.apk

# 3. (optional) Rust test suite
cd .. && cargo test --workspace

Architecture

The SSH transport is Rust (russh), running on a background thread with its own tokio runtime. Terminal rendering & input use the Termux engine (vendored, Apache-2.0). RTerm supplies the keyboard bar, credential/connection/macro storage, the foreground service, and the Compose UI shell.

rterm/
├── core/          rterm-core (Rust): JNI bridge — key encoder + SSH JNI → librterm_core.so
├── ssh/           rterm-ssh (Rust): SshSession over russh; forward + sftp modules; loopback tests
└── android/       Kotlin + Jetpack Compose app
    ├── terminal-emulator/   vendored Termux engine (Apache-2.0)
    ├── terminal-view/       vendored Termux view (Apache-2.0)
    └── app/                 RTerm app — UI, storage, foreground service, macros

More detail: ARCHITECTURE.md · ROADMAP.md · STATUS.md · upstream reviews in SECURITY-REVIEW-Rin.md and SECURITY-REVIEW-Termux.md.

License

The vendored Termux terminal engine (rterm/android/terminal-emulator, rterm/android/terminal-view) is Apache-2.0 — see the NOTICE.md in each module. RTerm's own application source is published here as-is.

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Built and published from source on a self-hosted Forgejo instance.