Link to macOS

Connect your Android phone to your Mac. Sync your clipboard both ways, lock your Mac from your phone, and let it lock itself when you walk away — directly over your Wi-Fi, or through a relay you host yourself when you're away. In the spirit of Microsoft's "Link to Windows", but self-hosted.

Personal-use project. Not intended for the Play Store / App Store.

Features

• 📋 Two-way clipboard — copy on the phone, paste on the Mac, and vice versa.
• 🔒 Lock from your phone — one tap on the Home screen locks your Mac.
• 🚶 Auto-lock when you leave — the Mac locks itself once your phone is out of Bluetooth range. (Locking only — macOS has no way to auto-unlock.)
• 🔋 Battery both ways — your Mac's charge shows on the phone's Home screen, and your phone's battery + name show on the Mac's dashboard, live.
• 🔔 Notification mirroring — Android notifications pop up on the Mac as native banners and collect in the dashboard's Notifications tab (one-way, pausable).
• 💬 Read your messages — your phone's SMS show up as conversation threads on the Mac's Messages tab, so you can read texts without unlocking your phone (read-only for now, pausable).
• 🖥️ Mac dashboard — a Material 3 menu-bar card plus a window showing your phone, clip history, notifications, and messages.
• 🔗 Pair once with a QR code shown on the Mac.
• 📶 No relay on the same Wi-Fi — the phone connects straight to the Mac (LAN-direct), and falls back to the relay automatically when you leave home. Works relay-free if you never set one up.
• 🏠 Self-hosted — the relay runs on your own server; nothing goes through a third party.

How it works

  Android phone                 your relay              Mac
  ┌─────────────────┐           ┌────────────┐        ┌───────────────┐
  │ background app  │  ◄─────►  │  tiny WS   │  ◄───► │ menubar app + │
  │  clipboard ·    │           │  server    │        │  dashboard    │
  │  lock · battery │           │ (room id)  │        │  clipboard ·  │
  │  notifications  │           │            │        │  lock · QR    │
  └───────┬─────────┘           └────────────┘        └───────┬───────┘
          │                                                   │
          └───────────  Bluetooth presence beacon  ───────────┘
                      (proximity auto-lock — fully local)

A small menu bar app on the Mac and a background app on Android stay connected. On the same Wi-Fi the phone connects straight to the Mac (the Mac runs a small local server it finds automatically) — no relay needed. When you're away, it falls back to a tiny relay server you host, routed only by a shared room id. Either way, clipboard text and the "Lock Mac" command are end-to-end encrypted. Proximity auto-lock uses neither: the phone broadcasts a Bluetooth presence beacon and the Mac locks itself when that signal fades — so it works even with no internet.

The Android trick: regular apps can't read the clipboard in the background, so the app connects to the phone's own ADB over Wireless Debugging and runs a tiny helper with the permissions to do clipboard I/O. It keeps working after the app is swiped away.

Components

Directory	What it is
mobile/	Expo (SDK 56) React Native app — pairing, settings, and the background service that does clipboard sync + the Bluetooth beacon.
mac/	Swift menu bar app — clipboard sync, remote lock, proximity auto-lock, pairing QR, login-item auto-start.
server/	Minimal Node.js WebSocket relay (room routing, auth token, rate limiting). Docker-ready. See server/README.md.
docs/	Design documents and implementation plans.

Getting started

1. Relay (optional) — only needed to sync while you're away from your Wi-Fi. On the same network the app works relay-free. To run one: cd server && npm install && npm run dev (or docker compose up -d). See server/README.md for env vars and reverse-proxy (wss) setup.
2. Mac app — open mac/LinkToMac.xcodeproj (generated from project.yml via XcodeGen) and run. LAN-direct is on by default (Server Settings… → LAN-direct); add a relay's address/port/TLS/password there only if you want away-from-home sync. Then show the pairing QR.
3. Android app — cd mobile && bun install, then build a dev client (npx expo run:android). Expo Go isn't supported (custom native module). Turn on Wireless Debugging and pair once by scanning the Mac's QR — it carries the LAN port (and relay address/password, if set), so the phone configures itself and prefers the direct LAN link automatically (editable later under Settings → Relay server).

Building a release (beta)

• macOS — cd mac && ./scripts/build-release.sh → build/release/LinkToMac-<version>.dmg (universal, ad-hoc signed). The app is not notarized (no Apple Developer team), so on a different Mac the first launch must be right-click → Open once — or run xattr -dr com.apple.quarantine /Applications/LinkToMac.app after dragging it in.
• Android — cd mobile && eas login && eas build --platform android --profile preview --local → an installable APK (sideload). This preview profile is the public-release build: it bakes in the preview EAS Update channel, so OTA JS patches must be published to the same channel (eas update --channel preview). The version in app.config.ts is the release identity; the versionCode is derived from the build date as YYMMDDNNN (bump BUILD_NUMBER only for a 2nd+ build the same day). Attach the APK to a GitHub release — the in-app updater discovers new versions from the latest GitHub release.

Using the features

• Clipboard — just copy on either device; the other one follows. You can pause sending from the phone in Settings while still receiving the Mac's copies.
• Lock Mac — tap Lock Mac on the phone's Home screen (needs the Mac connected).
• Auto-lock when you leave — turn it on in both apps: the phone's Settings (Auto-lock Mac when I leave) and the Mac menu (Lock when phone leaves). On the Mac you can tune Sensitivity (Near / Balanced / Far) and Lock after (10–60s), and watch the live signal to calibrate for your space.
• Notification mirroring — grant Notification access to the app once (Settings → Mirror notifications), and Android notifications appear on the Mac as banners and in the dashboard's Notifications tab. It's one-way and can be paused from the phone without revoking the system grant.
• Read your messages — grant SMS access once (Settings → Grant SMS access), and your recent texts plus new ones arrive as conversation threads on the Mac's Messages tab. It's read-only and one-way for now, and can be paused from the phone without revoking the grant.
• Battery & phone identity — the Mac's charge shows on the phone's Home screen; the phone's battery and name show on the Mac's dashboard. No setup — it rides the same connection.

Security & privacy

• Pair once: the Mac generates a random room id + key and shows them as a QR — along with the relay address, port, TLS setting, and password — so the phone configures itself in one scan. Secrets are stored in the Keychain (macOS) and Keystore-backed storage (Android).
• You own the relay: it routes messages by room id and never stores clipboard content. The endpoint, password, and TLS are configured at runtime (nothing is baked into the build); run it over TLS (wss) behind a reverse proxy on infrastructure you trust.
• LAN-direct is safe without TLS: on the local network the link is plain ws://, but the payloads are still end-to-end encrypted and the connection is gated by a challenge-response over your pairing key — a stranger on the Wi-Fi can neither read it nor impersonate your phone.
• Proximity lock is local: it uses Bluetooth only and never touches the relay or internet.
• End-to-end encrypted: clipboard, the lock command, battery telemetry, mirrored notifications, and mirrored messages are all sealed with ChaCha20-Poly1305, keyed by the secret exchanged at pairing. The relay (or anyone on your LAN) only ever sees opaque ciphertext — never your clipboard, the command, your notifications, your texts, or the key.

Scope & status

v1 links one phone and one Mac and syncs text only (images/files are out of scope; the 256 KB payload cap reflects that — mirrored app icons are small PNGs). Implemented: clipboard sync (end-to-end encrypted), remote lock, proximity auto-lock, LAN-direct mode, two-way battery/phone telemetry, one-way notification mirroring, and read-only SMS mirroring (phone → Mac). Screen mirroring, file transfer, replying to messages, and read-only Calls/Photos tabs are still on the roadmap. A separate technical document (TECHNICAL.md) covers the internals in depth.

License

Personal project — see mobile/LICENSE.