Link to Mac

Your Android phone and your Mac, working as one.

Two-way clipboard (text and images), lock your Mac from your phone, auto-lock when you walk away, mirrored notifications and messages, and live battery both ways — over your own 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 and yours end to end.

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

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Why

Your phone and your laptop should feel like one machine — copy here, paste there; walk away, it locks; a text arrives, you read it without reaching for your phone. The commercial versions of this route your clipboard and messages through someone else's cloud. Link to Mac does the same job, but nothing leaves hardware you control. On the same Wi-Fi it's a direct phone↔Mac link; away from home it falls back to a tiny relay you run. Either way the payloads are end-to-end encrypted — the relay only ever sees opaque ciphertext.

Features

	Feature
📋	Two-way clipboard	Copy text or an image on either device, and it lands on the other.
🔒	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 leaves Bluetooth range. (Lock-only — macOS can't auto-unlock.)
🔋	Battery both ways	Your Mac's charge shows on the phone; your phone's battery + name show on the Mac. Live.
🔔	Notification mirroring	Android notifications pop as native banners on the Mac and collect in a tab. (One-way, pausable.)
💬	Read your messages	Your SMS appear as conversation threads on the Mac. (Read-only for now, pausable.)
🖥️	Mac dashboard	A Material 3 menu-bar card + window: your phone, clip history, notifications, messages.
📶	LAN-direct, relay optional	Same Wi-Fi → straight to the Mac. Leave home → seamless relay fallback. Works relay-free if you never set one up.
🔗	Pair once	Scan one QR shown on the Mac. It carries everything the phone needs.
🏠	Self-hosted	The relay runs on your server. Nothing routes 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 ·  │
  │  notifs · SMS   │           │            │        │  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 (which runs a tiny local server the phone discovers automatically) — no relay in the loop.
• Away from home, it falls back to a small relay you host, routed only by a shared room id.
• Either way, clipboard content and the "Lock Mac" command are end-to-end encrypted (ChaCha20-Poly1305, keyed by the secret you exchange at pairing).
• Proximity auto-lock uses neither path: the phone broadcasts a Bluetooth presence beacon and the Mac locks itself when the signal fades — so it works even with no internet.

The Android trick: ordinary 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 privileged helper with clipboard I/O permissions. It keeps working after you swipe the app away.

Components

Directory	What it is
mobile/	Expo (SDK 56) React Native app — pairing, settings, and the background service doing clipboard sync + the Bluetooth beacon.
mac/	Swift menu-bar app + dashboard — 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. Text and images both sync both ways. You can pause sending from the phone in Settings while still receiving the Mac's copies, and there's a separate Send images switch if you want text-only in one direction.
• 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 (10–60 s), 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. One-way; pausable from the phone without revoking the 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. Read-only and one-way for now; pausable 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 live in the Keychain (macOS) and Keystore-backed storage (Android).
• You own the relay. It routes messages by room id and never stores 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. Bluetooth only — never touches the relay or the internet.
• End-to-end encrypted. Clipboard text and images, 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, your images, the command, your notifications, your texts, or the key.

Scope & status

v1 links one phone and one Mac. Shipping today:

• ✅ Two-way clipboard — text and images (end-to-end encrypted; ~1 MiB payload cap, so an image is downscaled to fit)
• ✅ Remote lock & proximity auto-lock
• ✅ LAN-direct mode with automatic relay fallback
• ✅ Two-way battery / phone telemetry
• ✅ One-way notification mirroring
• ✅ Read-only SMS mirroring (phone → Mac)

On the roadmap: arbitrary file transfer (beyond clipboard images), screen mirroring, replying to messages, and read-only Calls / Photos tabs. A separate technical document (TECHNICAL.md) covers the internals in depth.

License

Personal project — see mobile/LICENSE.