Share windows
between your Macs.

Screen sharing shows you a whole desktop inside a window, so you end up working in a window within a window. Beam gives you the window itself. It sits on your desktop at its own size, with its own Dock icon, in your ⌘ Tab.

No, and they solve different problems. Universal Control shares one keyboard and mouse between Macs sitting side by side. Beam brings a window from a Mac in another room, or another building, onto the one in front of you.

By default the window stays where it is on that Mac and you use it in place, so anyone sitting there watches it work, pointer and all. Switch it to Fluid in the gear card and the window leaves that screen for yours at full resolution; a small capsule under the menu bar says where it is and brings it back with a click. To stop other Macs taking windows over at all, turn on "Keep windows on this Mac" in Settings.

No. Your Macs talk to each other directly, over your own network at home and over your tailnet when you are apart. There is no account to make and nothing to relay through, so nobody else is ever in the path.

Two Macs on macOS Sonoma or later, with Beam installed on both. Being on the same network is enough on its own; Tailscale is optional and only earns its keep when the Macs are apart. When macOS asks whether Beam may find devices on your local network, click Allow (you can change it later under System Settings › Privacy & Security › Local Network). The Mac doing the sharing grants Screen Recording and Accessibility once.

Beam is signed with a Developer ID and notarized by Apple, and the download carries that ticket, so this dialog should not appear. If it does, open System Settings › Privacy & Security, scroll down to the line that says Beam was blocked, and click Open Anyway; you only do this once. If it keeps happening, download Beam again from this page rather than from a copy that was passed around, then run beam doctor from Terminal inside the app bundle to see what Gatekeeper thinks of the install.

$49, once. That covers every Mac you use, so there is nothing to buy for the second machine. There is no subscription.

Not right now. Beam is a one-time purchase, and the download starts the moment you buy.

Only what you pick. You beam one window at a time, or a whole display if you choose one. Hidden apps and password managers never reach the list at all, and you can stop any share from the menu bar.

Yes. Beam prints a link that opens that one window in any browser, on any device. It is view only unless you say otherwise, and it expires after an hour.

Yes, and that is half the point. A headless Mac mini or Studio running builds or agents lists its windows like any other Mac, and there is a command line and a doctor for setting one up over SSH.