yeksax
← Back to home

Tether

Daemon and app

Your Mac and Android, within reach.

I built Tether to connect the two devices I use every day. From either one, I can check battery status and adjust the other’s volume, brightness, theme, and Do Not Disturb. A Mac daemon and Android app communicate directly over my private Tailscale network, without an intermediary server. Each interface shows the other device’s wallpaper and live state. The desktop app also mirrors Android at a stable 60 fps, accepts remote input, and follows screen rotation.

Stack

language

Kotlin 01 language Kotlin The phone side: the app and the client that talks to the daemon. kotlinlang.org Swift 02 language Swift The Mac daemon talks directly to IOKit, CoreAudio and CoreWLAN. swift.org

front-end

Jetpack Compose 03 interface Jetpack Compose The whole interface, including the 3D portrait of the other device. developer.android.com

data

SQLite 04 database SQLite Pairing state on the daemon's side, so a restart stays paired. sqlite.org

infra

Tailscale 05 network Tailscale Transport and identity, with all authorization coming from `whois`. tailscale.com
01 transport

Tailnet

The devices talk directly over Tailscale, and identity comes from `whois`. There is no account, no token and no server in the middle.

  • No broker between them
  • Pull on demand, not a polling loop
02 control

Both directions

Whichever device is in your hand can check battery and network status, then control volume, brightness, theme, and Do Not Disturb.

  • Direct access to system frameworks
  • Same protocol either way
03 presence no cloud

The other device

Each app renders the other device with its actual wallpaper and live state: the phone in the desktop preview, and the Mac on a 3D MacBook screen.

  • Real wallpaper, not a mockup
  • Live state inside the portrait