Get started  ·  What's new in 3.1  ·  How it works  ·  Build it  ·  Docs

RemEx runs your PC from your phone over plain LAN: no relay server, no account, no subscription. It's an Android app plus a Windows/Linux agent. Screen streaming, remote input, file transfer, clipboard sync, wake-on-LAN, power control, live sensors and routines, with just the two devices talking directly to each other.

3.0 is the biggest release yet. 296 commits and 1,436 files changed since 2.5.0, a new look shared across both apps, routines that act on their own, and a startup splash that actually shows RemEx finding your PC. It's also the first release in production on Google Play.

What's new in 3.1

3.1 redesigns file sharing on both apps. The PC and the phone now show both devices in one folder tree, preview the file you pick, and show the SHA-256 fingerprint that proves a file arrived exactly as it was sent.

🗂️ One tree, both devices The PC's File Transfer page and the phone's Files screen list This PC (or This phone) and the other device side by side. Open folders level by level; the tree follows you as you browse.	👁️ Live preview Pick a file to see it: photos at full quality with zoom, and text, code and logs in colour with line numbers. Turn on Live to follow a log as it grows.	🔐 SHA-256 you can see Transfers say Verified when the fingerprint really matched. Copy a file's fingerprint, compare it with one you paste, or check it against the copy on the other device.
↔️ Send between devices Send to PC and Save to phone into any folder you pick, and on the PC drag files from one device to the other. Everything goes through the same verified transfer queue.	📁 Phone folders you choose Add folders from your phone to browse them in RemEx. Your PC only sees one when you turn on Share with PC.	📷 Scan to get the phone app The PC's Home page shows a QR code that opens RemEx on Google Play.

The full 3.1 write-up is in the release notes.

What's new in 3.0

⚡ Routines Your phone acts on its own. Start a routine when you get home (spotted from your Wi-Fi, so no location permission), tap an NFC tag, or when a PC sensor passes a limit. Put one on the home screen as a shortcut or a widget that shows its last result.	🖥️ Routines on the PC The PC can run a routine itself when it goes idle, or locks or unlocks, even with your phone away. It keeps a history, lets you pause everything or block a phone, and shut down, restart and sleep always show a countdown first.	🎨 One look, two apps A fresh install of either app starts on the same RemEx colours. Cards, page titles, fonts and page names (Sensors, Commands, Apps, Processes, Files) now match on the PC and the phone.
🚀 A new startup splash Live Handshake is the new default: it plays RemEx actually starting and finding your PC. Three more scenes are one tap away. See them below.	📱 A new phone layout Five tabs: Home, Desktop, Apps, Control, More. Sensors is a grid you can edit by holding a card: move, resize, remove, add, or pin to Home. Pick 2, 3 or 4 columns, or let Auto decide.	🔔 Alerts and logs The sensor alert rules you set on the PC arrive as notifications on your phone. Critical alerts pop up, warnings arrive quietly. The PC's logs and health checks are a page away in More, with anything private hidden before it's sent.
🗂️ Browse your phone from the PC The Files page has a Source picker: This PC or any connected phone. Browse the folders the phone shares, search them, see thumbnails, download. With one off-by-default switch on the phone, change files there too.	✨ Make it yours App backgrounds (six textures and three slow animated styles), six more card shapes and seven Nerd Fonts bundled in the app. Screens slide in, readings roll when they change, and switches give a short haptic buzz. Everything respects Remove animations.	🔒 Tighter by default Apps and links RemEx opens on your PC run with your normal permissions, not administrator. The phone only opens folders you share, and checks your current Access settings on every request.

The full 3.0 write-up is in the release notes, and every change is in the changelog.

The splash

Every launch opens on one of four scenes. Pick yours in Personalize.

Scene	What you see
Live Handshake (default)	RemEx starting up and finding your PC, beat by beat.
Original Scan	A command deck: perspective grid floor, falling data columns and scanlines, with shockwave sweeps on every beat.
Cosmic Zoom	Flying through a nebula, three star layers stretching into warp streaks as the mark assembles.
Pong	A phosphor CRT court with glowing rails, heating up through the rally until the mark lands.

All four share one shader on Android and the PC, and Original Scan, Cosmic Zoom and Pong settle on a still frame when Reduced motion is on.

Get started in five minutes

	Step
1	Install the Android app from Google Play (package com.clindsay94.remex). Prefer to sideload? The APK is on GitHub Releases, see sideloading on Samsung.
2	Install the PC agent from GitHub Releases (table below).
3	Pair. Open the agent on the PC and RemEx on the phone, on the same Wi-Fi. The PC shows a 6-digit PIN (it expires in 2 minutes), you type it into the phone, done. While no phone is connected, Pair a phone on the PC's Home screen opens Settings with the QR code and PIN ready. Full walkthrough in docs/INSTALL-ANDROID.md.

Platform	Download	Size
Windows	RemEx-v3.1.0-Setup.exe (Inno Setup, installs to run elevated for input and power control)	—
Android	RemEx-V3.1.0-release.apk (sideload)	38.6 MB
Linux x64	remex-agent-v3.1.0-linux-x64.tar.gz, see Linux install	70.1 MB

Requires: Android 14 or newer on the phone, a Windows or Linux PC, and both on the same network. To reach your PC from elsewhere, run Tailscale on both ends, because RemEx has no relay of its own.

sequenceDiagram
    participant Phone as Android (client)
    participant PC as remex.agent (host)
    Phone->>PC: discover on LAN
    Phone->>PC: ECDH P-256 key exchange
    Note over PC: PC displays a 6-digit PIN, expires in 2 minutes
    Phone->>PC: type PIN, confirm
    PC-->>Phone: SPKI certificate pin (stored for future connections)
    Phone->>PC: WSS /ws (control), WSS /ws/desktop (video), TCP+TLS :8338 (scripts)

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Upgrading from 2.5

Install the new PC app over the old one. Your settings, paired phones and layout stay, and nothing about pairing or certificates changed, so you don't pair again. Update the PC and the phone together: a PC older than 3.0 still works with the 3.0 phone app, just without sensor alerts, the logs page, shared pinned sensors and PC-run routines.

Everything it does

The full feature list

• Remote desktop screen streaming (H.264, on-demand keyframes, configurable and rate-limited fps), with remote input including stylus and two-finger scroll
• Routines: arrive or leave home, NFC tap, or PC sensor thresholds, run on the phone or on the PC itself
• Live sensors as an editable grid, pinned sensors shared between phone and PC, and alert rules that notify your phone
• File transfer both ways: whole folders, name-collision handling (Replace, Keep both, Skip, apply to all), speed and ETA, and browsing and optionally changing your phone's shared folders from the PC
• App launcher (allowlisted, no arbitrary or network paths) and a Processes page
• Power controls with a countdown, Wake-on-LAN without typing a MAC address
• Clipboard sync, phone to PC
• Multi-monitor support, including monitors placed above or left of the origin
• The PC's logs and diagnostics, readable from the phone
• Personalize: seed-based colour palettes with a colour wheel and live preview, Material You dynamic colour, backgrounds, card shapes, Nerd Fonts, four splash scenes, motion and haptics
• Paired-device management: rename or unpair from Settings, tap to connect from the phone
• First-run tutorial on both apps and a Home-screen readiness check (admin rights, certificate, firewall, start at sign-in)
• Localized in 9 languages: en, es, fr, hi, id, pl, pt-BR, tr, uk

Sideloading on Android (Samsung notes)

If you install the APK from GitHub Releases instead of Google Play:

• Android will prompt once to allow installs from the source you opened the file with ("unknown sources"), as it does for any APK not installed through Play.
• Samsung phones also ship Auto Blocker, which can block sideloaded installs by default. If the install is silently refused, check Settings → Security and privacy → Auto Blocker and allow the install (or turn it off for the install).
• Sideloaded builds don't update themselves. Come back to Releases for the next version, or switch to Play.

See docs/INSTALL-ANDROID.md for the full walkthrough.

How it talks to your PC

flowchart LR
    A[Android app] -- "WSS /ws :5005<br/>telemetry, pairing, files" --> P[remex.agent]
    A -- "WSS /ws/desktop :5005<br/>H.264 / MJPEG" --> P
    S[external script] -- "TCP+TLS :8338<br/>paired clientId required" --> P

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Channel	Port	Carries
WSS /ws	5005	telemetry, power control, pairing, file transfer
WSS /ws/desktop	5005	remote desktop video (H.264/MJPEG)
TCP+TLS	8338	external script ingress, requires a paired client ID

Pairing is ECDH P-256 key exchange plus a 6-digit PIN shown on the PC and typed on the phone, then SPKI certificate pinning for every connection after that, over TLS 1.3 (1.2 accepted). There's no cloud relay, no account, and no telemetry leaves your network. See docs/SECURITY_EXPLAINED.md for how it works and docs/SECURITY.md for the reporting policy.

Building from source

git clone https://github.com/clindsay94/RemEx.git
cd RemEx
./build-remex.ps1 -Target all -Config release   # PC + Android, one command
./scripts/verify.ps1                             # clean build + .NET test suite, writes a receipt
./scripts/verify.ps1 -Scope all                  # plus Android release tests and lintRelease
./scripts/verify.ps1 -Check                      # does the last receipt still match the code on disk?

Toolchain versions and project layout

• .NET SDK 10.0.x, Avalonia 12.1.1 (remex.desktop)
• Kotlin 2.3.21, AGP 9.2.1, Gradle 9.4.1, JDK 17, Compose UI 1.12.0-beta02 with Material3 1.5.0-alpha24 (remex.android)
• remex.core, shared protocol/models (RemexMessage, DesktopMeta, TelemetryPayload), targets net10.0 and net10.0-android
• remex.agent / remex.agent.windows / remex.agent.native.linux, the PC host and its platform backends
• remex.desktop, Avalonia UI (Personalize, dashboard, tray)
• remex.android, the Kotlin/Compose client
• remex.branding, shared branding assets and the splash scenes
• installer/, Inno Setup (RemEx.iss) for Windows, packaging scripts for Linux
• *.tests projects per component, plus remex.desktop.render.tests for UI screenshot/automation checks

Full build docs: docs/BUILDING.md. CI runs on GitHub Actions: .github/workflows/dotnet.yml builds and tests Windows + Linux on every PR to main, and .github/workflows/localization-check.yml checks all 9 languages for missing, stale, unused, or format-mismatched keys.

Contributing

See docs/CONTRIBUTING.md and docs/CODE_OF_CONDUCT.md. This repo is developed with Claude Code; .claude/CLAUDE.md has the project rules (architecture invariants, the verification gate, coding conventions) if you're pairing an agent with it.

Warning

Read docs/REGRESSION-GUARDS.md before touching capture, the remote-desktop stream/pacing, the Android H.264 decoder, SurfaceView zoom/pan, pairing/trust, or the session guard. Every rule in there exists because breaking it reintroduced a real failure that showed up as silence, a black screen, a dead stream, a bricked pairing, with no log line pointing back at the cause.

Reporting a security issue

Please don't open a public issue for a vulnerability. See docs/SECURITY.md for how to report privately.

Docs index

Doc	What's in it
docs/RELEASE-NOTES-3.1.0.md	Readable summary of everything in 3.1
docs/RELEASE-NOTES-3.0.0.md	Readable summary of everything in 3.0
docs/CHANGELOG.md	Full changelog, all versions
docs/INSTALL-ANDROID.md	Google Play, sideloading, Auto Blocker, first pairing
docs/ANDROID_SETUP.md	Android dev environment / SDK setup
docs/LINUX_INSTALL.md	Linux agent install and dependencies
docs/BUILDING.md	Full build instructions, all platforms
docs/ARCHITECTURE-HOST.md	PC agent architecture
docs/API_CONTRACTS.md	Message/protocol contracts between client and host
docs/FILE_SHARING.md	File transfer design
docs/SECURITY.md	Vulnerability reporting policy
docs/SECURITY_EXPLAINED.md	How pairing, pinning, and the channels work
docs/CONTRIBUTING.md	How to contribute
docs/CODE_OF_CONDUCT.md	Code of conduct
docs/REGRESSION-GUARDS.md	Guards against known silent-failure regressions
docs/FAQ-PARITY.md	Developer doc: the 16 FAQ questions both apps must answer, and the parity rule
docs/ASYNC_GUIDELINES.md	Async coding conventions
docs/NULL_SAFETY_GUIDELINES.md	Null-safety conventions
docs/VALIDATION_GUIDELINES.md	Input validation conventions
.claude/CLAUDE.md	Project rules for coding agents

License

MIT. See LICENSE.