Who can see your journal, in plain language.

The short answer is nobody. Not your doctor, not your family, not us, not a researcher. What you write sits encrypted on your device and stays yours until you decide otherwise.

Here is what that means in practice, because "private" is a word that gets used loosely.

Encrypted before it leaves your phone

Your recording is scrambled on your device before it is sent anywhere. What travels is unreadable without your key. That is true whether you are on hospital wifi or a train.

Sharing is per item, and reversible

You do not switch on sharing. You share a summary, or a result, or a check-in, with a person you name. Each one is its own decision, and you can withdraw any of them later without explaining yourself.

Turning something off does not delete it from your record. It stops the other person seeing it from that point.

Nobody is monitoring it

This is the part worth being blunt about. Care Journal is not watched. If you write that you cannot keep fluids down, no alarm goes off anywhere. It is a record you keep, not a line to your care team, and it is never a way to reach anyone urgently.

If you think you are having a medical emergency, call your local emergency number or go to the nearest emergency room.

Research is a separate question, asked later

Care Journal is free because researchers pay to understand how treatments actually feel. That is a decision you make on its own, long after you sign up, with the recipient named before you agree. You can turn it off whenever you like and it lapses after a year unless you renew it.

If you never opt in, nothing leaves your phone, and the app works exactly the same.