Relief is closed source, so "nothing you write leaves the phone" is a claim you cannot read the code to check. You can check it a different way, in about a minute, with a tool already on your iPhone.
That report is produced by iOS, not by us. We cannot influence what it says.
If you have never opened the paywall and never bought anything, the honest expectation is no network activity at all. The app works entirely offline.
If you have opened the paywall, restored a purchase, or subscribed, you should see RevenueCat domains. RevenueCat handles subscription status so that a purchase keeps working across reinstalls and devices. It receives purchase information and an anonymous, app-generated identifier — no name, no email, and none of your writing.
That is the complete list. There is nothing else.
App Privacy Report is the easy route. If you would rather watch the traffic directly, put the phone behind a proxy — Proxyman, Charles or mitmproxy all work — and use the app. You will see the same thing, in more detail.
If you find something on this page to be wrong, please say so: farid.jafarlee@gmail.com. A correction is worth more to this project than the claim was.
Watching the network proves what leaves the device. It does not prove what happens on it — for that you would need the source, and Relief is closed source. What can be said is that the entries are encrypted on the device with AES-GCM and the key is held in the iOS keychain, and that there is no server to receive them regardless.
Nothing here has been independently audited. It is a description of how the app behaves, offered in a form you can check rather than one you have to believe.