Questions, answered straight.

A free app for your Mac, your Windows PC, your iPhone and your Android phone. It sends files straight between them over the Wi-Fi you are already on.

There is no account to make, no cloud to upload to, and no server in the middle. The apps find each other on the local network and push the bytes directly.

Yes, in both directions, and that is the reason the iPhone app exists. Two phones from different makers sitting on the same table have never had a simple way to hand each other a photo.

Beam runs the same protocol at both ends, so they do. The same goes for an iPhone and a Windows PC, or an Android phone and a Mac.

No, because there is no server to reach. Both devices have to be on the same network and the file goes straight from one to the other. Take a device off the local network and Beam has nobody to talk to.

No account, no sign-in, no analytics. Read the privacy policy.

Check the version first: two devices only talk when their protocol numbers match. On Mac, Windows and Android it is under Settings › Version. A device on another version is still listed, with which side needs updating.

On Windows, Beam says so when Windows Firewall is blocking it, and Allow fixes it in one step. Guest and office Wi-Fi often keep devices from seeing each other at all; a phone hotspot or your home network will work.

Yes. Beam needs the devices on the same network, not on the internet, and a phone’s hotspot is a network. Turn the hotspot on on one phone and join it from the other devices. The phone sharing the hotspot can send and receive too.

The files go straight across the hotspot, so they do not use your mobile data. The same trick works on guest or office Wi-Fi that keeps devices from seeing each other.

What arrived is kept. The receiver holds on to the partial file, so sending the same thing again picks up where it stopped rather than starting from zero. The same applies when you press Stop on purpose.

Partial files that nobody comes back for are cleaned up after seven days.

The sender hashes the file while it streams and sends the SHA-256 once the bytes are through. The receiver writes into a staging file first, checks the hash across the whole file, and only then moves it into your save folder.

A transfer that fails the check never becomes a file that looks finished. It is discarded, and the sender is told exactly which file needs sending again.

Every device holds a private key. At the start of each transfer both devices sign a challenge that includes fresh random values from the other, so each proves who it is instead of just claiming a name.

“Always accept from this device” pins that key’s fingerprint, which is printed on the prompt so two people can read it to each other. If a device you accepted before turns up with a different key, Beam never accepts it on its own: it asks you again, and the prompt in the app says the key has changed.

Yes, from one device to the other. The two devices agree keys for that transfer alone and forget them afterwards, and everything after the two devices swap keys is sealed with AES-256-GCM: file names, text and the files themselves. A byte changed on the way stops the transfer rather than slipping into your file.

Before anything is sent, both devices prove who they are with their own keys, and the sender checks that the device answering is the one you tapped. Someone else on the same Wi-Fi can see the device names Beam announces and that two of them are talking, but not what they send.

SmartScreen shows “Windows protected your PC” for installers it has not seen many times before. Choose More info › Run anyway. Beam installs for your account only, so installing needs no administrator rights. The one time Windows may ask is when you press Allow to let Beam through the firewall.

Files Beam receives on Windows are marked as coming from another computer, the same way a browser marks a download, so Windows checks a received program before running it.

iOS will not let an app keep listening on the network in the background. The Mac lives in the menu bar, Windows in the tray and Android runs a background service, so all three keep receiving whatever you are doing. The iPhone has to be open on screen.

Not yet. Zip it first and send the archive. Folders are on the list.

macOS 14 Sonoma or later on Apple silicon and Intel, Windows 10 or 11 (64-bit), Android 10 or later, and iOS 17 or later. Both devices need to be on the same network; Beam does not use Bluetooth or mobile data.