Running a headless Mac mini from your desk

A Mac mini does its best work when nobody is sitting at it. It runs the long build, the test suite, the agent that has been going since lunch, and it does all of that without a display, a keyboard or a chair. The catch has always been the moment you need to look at something.

Beam treats a headless Mac like any other Mac. Its windows list in the picker the same way, and any one of them opens on the machine in front of you. This post is the setup, start to finish.

What you need

• Two Macs on macOS Sonoma or later, with Beam installed on both.
• The same network. Wi-Fi is enough. If the mini lives somewhere else, Tailscale on both Macs does the rest.
• A way to reach the mini once, to grant permissions. Screen Sharing, a temporarily attached display, or SSH.

Setting up the mini

Install Beam on the mini and open it once. macOS will ask for two permissions on the Mac doing the sharing: Screen Recording, so Beam can capture the window it is sharing, and Accessibility, so it can deliver your input to it. Both are granted once and remembered.

If the mini has no display attached, the easiest route is over SSH. Beam ships a command line with a doctor that checks the permissions and the network on that Mac, and whether the other Mac can reach it, and tells you which step is missing. Run it, follow what it says, and you are done with the closet.

Pair the two Macs from the Mac at your desk. Pairing is a one-time handshake between the two machines; after it, the connection is pinned to those Macs and nothing else can join it.

Day to day

From then on, the mini's windows appear in Beam's picker on your desk Mac. Pick the terminal running the build and it opens as a window. Pick the browser the agent is driving and watch it work. Pick both and put them side by side.

Because nothing changes on the mini's own screen, there is nothing to tidy up afterwards. Close the beamed window and the app carries on over there exactly as it was.

The tradeoff

A Mac with no display has no display to capture, so Beam gives the mini a virtual one on its behalf, at Retina density. That works well for apps with ordinary windows. Apps that insist on going full-screen, or that draw their own custom chrome, occasionally behave differently on a virtual display than on a real one.

For the things a mini is actually for, builds, tests, agents and the odd long-running script, the setup above is all there is to it. The mini stays in the closet. Its windows come to you.