Privacy

Union connects your own machines to each other. Here is what it keeps to do that, and what it does not.

Last updated October 4, 2026.

What we keep

• Your account: your email address and the ways you sign in (a password, Apple, Google). Passwords are stored hashed by our sign-in provider; we never see them.
• If you sign in with Apple or Google: the email address and the account identifier they give us, and from Google also your name and profile picture. They are kept with your account to sign you in and are not used for anything else. Apple may give us a private relay address instead of your own.
• Your devices: each device’s name, what kind of device it is, an identifier the app makes for it, and when it last connected, so your devices can be listed for you. You can rename or remove them.
• Your plan: whether the account is on the free plan, in its free trial (and when that ends) or on Union Pro. For Union Pro: monthly or yearly, when it renews or ends, and the store’s own identifier for the subscription (the App Store’s transaction number, or the website subscription’s), so every device of the account knows it has Pro. We never see your card or bank details: Apple or Link takes the payment.

What we don’t

• What is on your screens, the sound, what you type and click, your clipboard and the files you send all go between your own machines. None of it is stored on our servers.
• No advertising, no analytics, no tracking. Nothing is sold or shared with anyone for their own use.

How your machines connect

• To find each other, your devices keep a connection to our signaling server. It passes on the short messages that set up a connection between two of your devices, never what the connection then carries.
• Over the internet, connections are encrypted end to end. When two machines cannot reach each other directly, the encrypted traffic goes through a relay server we run, which cannot read it.
• On your own local network, your machines can connect to each other directly.
• When you sign one of your devices back in from another, the password or the sign-in it needs goes over that encrypted connection between the two.

Who helps us run it

• Supabase: accounts and the device list.
• Cloudflare: this website, the web app and the downloads.
• Sakura Internet (Japan): the servers for signaling and the relay.
• OVH (United States): a relay server closer to devices in the Americas.
• Sentry: crash reports from the Mac, iPhone and Windows apps, and how their connections went (see below).
• Apple: Union Pro bought in the App Store, and sign-in if you choose it.
• Link (by Stripe): Union Pro bought on the website. It takes the payment and handles tax and receipts.
• Google: only if you choose to sign in with it.

On your devices

• The apps keep logs on the device to help work out problems. They are not sent anywhere unless you send them to us.
• When the Mac, iPhone or Windows app crashes, it sends a crash report to Sentry: where in the app it failed, the app and system versions and the kind of device. It carries no account, no screenshot and nothing from your screens, clipboard or files.
• The iPhone, Mac and Windows apps also tell Sentry, for each time they show another of your devices, how long that lasted, how long the picture took to come and how late it arrived, whether it went over the local network, directly or through a relay, and which codec and graphics chip made and showed it. The iPhone app adds how long it took to start and to show its screens, and when drawing them was slow. This carries the same versions and kinds of device, and no account, addresses, device names or file names, and nothing from your screens.
• Your sign-in stays on the device, in the keychain (on Windows, encrypted for your Windows account). If you turn on staying signed in, the account’s password is kept there too, so the device can sign itself back in.
• The web app keeps an identifier for your browser and your settings in the browser’s storage.

Deleting your data

Delete your account from Union’s account settings or from the web app. Your account, its sign-in methods, its device list and its plan are deleted, and every device signed in with it loses access. A Union Pro subscription is not cancelled with it: cancel that in the App Store or at app.link.com.

Contact

Questions about privacy: [email protected].