Questions people ask

Short answers, with links to the pages that go into detail.

What is Transfer Me It?

A macOS menu bar app that sends a file from one Mac to another. The sending Mac encrypts the file before it is uploaded, and only the receiving Mac holds the key that opens it. The server stores the encrypted bytes until the recipient collects them.

Does it cost anything?

No. The app is free to download and there is nothing to buy. A single file can be up to 500 MB, and a device can send 5 GB a day and 50 GB a month. The limits exist so that one person cannot spend the bandwidth of everybody else.

Do I need an account?

No. There is no email, password or sign-up. Your Mac generates a key pair the first time you run the app, the private half stays in the Keychain, and that key pair is your identity.

How is it different from AirDrop?

AirDrop needs the two Macs to be near each other, on Wi-Fi and Bluetooth. Transfer Me It works over the internet, so the two Macs can be in different countries, and the transfer does not depend on them being awake at the same moment.

Does it work with Windows, Android or iPhone?

No. Both ends must be a Mac running macOS 15 or later. The client is a macOS app and there is no web or mobile version.

How does the recipient get the file?

The recipient's Mac shows three words. They give those words to the sender, who types them in and picks a file. The words expire ten minutes after they are issued, and asking for new ones stops the old ones working immediately.

How long are files kept on the server?

The stored copy is deleted as soon as the recipient's Mac confirms it has the file. A transfer that is never collected expires after 24 hours, at which point the stored object is deleted.

Can the server read my files?

No. The file is encrypted with ChaCha20-Poly1305 on the sending Mac, and the key to it is sealed to the recipient's public key using HPKE with X25519. The server holds the ciphertext and the sealed key, and does not have the material to open either. It does see file sizes, timing, and which device sent to which device.

Is it open source?

Yes. The client and the server are both open source, and the server is yours to run. Point the app at your own and nothing about the encryption changes.