Show HN: Coast – Turn an iPhone into a control surface for a Mac

Love the clean concept! As a fellow Mac developer, I've always wanted a dedicated touch controller for quick workspace actions. How’s the latency over local Wi-Fi vs USB?

Author here. Coast lets you build a control surface for your Mac on an iPhone, iPad or Apple Watch. You lay out a grid, put whatever controls you want on it, and the Mac executes them as real input events, so it works with every app already installed without plugins or per app integration.

The editor is the core of it. You pick a canvas up to 8 by 12 and place controls from a palette: keys and modifier chords, hold keys, sticky keys that latch on tap, two stroke chords like Cmd K Cmd S, D-pads, jog wheels with per detent actions and speed sensitivity, rockers and turbo keys that repeat while held, joysticks, mouse buttons, a numpad, media keys, a volume slider bound to CoreAudio, scroll strips, text macros, URL openers, and app launchers that fetch your Mac's actual installed app list and real icons over the wire. Tap a control to configure it, drag to move, corner handle to resize. Layouts are JSON and sync through iCloud.

Decks ship for Photoshop, Final Cut, Premiere, Lightroom, OBS and VS Code. The Premiere one has a weighted jog wheel for scrubbing that turned out to be the control I use most. There is also a full multitouch trackpad with the native gesture vocabulary, a remote keyboard that streams keystrokes as events rather than holding text locally, and a mode that turns a grid into an emulated game controller with twin sticks, which plays through keyboard and mouse so it drives anything with rebindable controls.

Any number of phones can connect at once. Exactly one is active and drives the Mac while the rest stay live in standby, and held input is released on every switch.

There is no account and no server. Nothing leaves your local network, and there is no analytics or telemetry anywhere in either app.

The iOS app is free with a $2.99 one time unlock for the full toolkit, and the Mac app is free.