Last updated 14 October 2026
tether has no accounts and no analytics, and your letters never pass through a server of ours. They travel through your own iCloud account and the iCloud account of the person you send them to. The developer can't read them, and neither can anyone else except the two of you.
Two other things are involved, and neither sees your letters, your name, your photo or where you are: RevenueCat, which checks tether+ purchases, and tether's widget relay, which only wakes widgets (see Your widget).
Your profile: your name, the photo you choose (if any), your city, and your approximate location.
Your letters: what you wrote, the ink and handwriting you chose, when each one was sent, and when it was opened.
Both live in iCloud, inside the friendship you share with each person, so that person can see them. A copy is kept on your iPhone so the app opens instantly and works offline.
Letters, your name, photo, city and location are end-to-end encrypted with keys held in iCloud Keychain and shared only with the other person in each friendship. The rest (identifiers, dates, which ink and handwriting you used, and whether a letter has been opened) is stored with iCloud's standard protection, which is how iCloud knows where to deliver things.
Only the people you're connected to, and only what's in your friendship with them: your profile and the letters between you. Nobody can join a friendship without an invitation, and each invitation works once, for the first person who opens it, and never again.
tether asks where you are only while it's open, at most once an hour, and takes a single approximate reading. Before it's stored or shared, it's rounded to a tenth of a degree, about 10 km, so it can place you in a city, never on a street.
To name your city, tether looks the rounded point up with Apple Maps. Location is optional: you can type your city instead, and you can turn location off for tether at any time in Settings.
If you speak a letter instead of typing it, your iPhone's speech recognition turns your words into text. Where your iPhone supports it, that happens entirely on the device. Where it doesn't, Apple processes the audio to transcribe it, under Apple's privacy policy. tether never records or keeps audio.
If you allow them, tether tells you when a letter has landed. The notification is made on your iPhone and says only who it's from.
If you add tether's widget, iOS gives it a push address. tether keeps that address in your profile, encrypted like the rest of it, so the people you're connected to can wake your widget when they throw something at you.
To wake it, their tether sends your widget's push address to tether's relay, a small service the developer runs on Netlify, which asks Apple to refresh your widget. The relay receives that address and whether it belongs to a test build, nothing else: no letter, no name, nothing about either of you. It keeps none of it, though like any web service Netlify may log basic request details, such as an IP address, for a short time. Your widget then fetches what was thrown from iCloud itself.
tether+ is bought with your Apple Account, and Apple handles the payment; tether never sees your card.
To know whether you have tether+, tether uses RevenueCat. It receives a random identifier made just for this app, what you've bought and when, and basic details such as your country, currency, device model and app version. It doesn't receive your letters, your profile or your location, and it isn't used to advertise to you. RevenueCat's own privacy policy covers what it keeps.
No analytics. No advertising. No tracking across apps or websites. Nothing is sold. The developer has no access to your letters, your profile or anything else you keep in tether; the only thing that ever reaches a service of the developer's is a widget's push address, on its way to Apple.
iCloud, Apple Maps, notifications and speech recognition are provided by Apple and covered by Apple's own privacy policy.
Removing someone ends your friendship with them: it disappears for both of you, with every letter in it.
Settings → Delete my data removes everything: friendships you started are deleted for both of you, you leave the ones you joined, and everything on this iPhone is erased. It can't be undone.
Deleting the app removes only the copy on your iPhone; what's in iCloud stays until you use Delete my data, or remove tether's data in your iPhone's iCloud storage settings.
tether isn't meant for children under 13, and doesn't knowingly hold their information.
If this policy changes, the new version will be here and in the app, with its date at the top. Questions go to the developer at ashwinnanbazhagan@gmail.com.