Privacy policy
JointSignal · Last updated 26 September 2026
The short version
JointSignal keeps everything on your phone. There is no account, no server, and no analytics. I do not receive your health information — not in summary form, not anonymised, not ever. The app has no code capable of sending it to me.
Everything below is the detail behind that sentence.
Who this is from
JointSignal is made by Scott, an individual developer in New Zealand. I built it to track my own rheumatoid arthritis, and I use it every day for the same purpose you do.
What JointSignal records
Only what you enter:
- Daily ratings — pain, how you are overall, fatigue, morning stiffness, sleep, mood, and whether it was a flare day
- Joint counts you tap in yourself
- Weekly function questions
- Medicines, doses and whether you took them
- Blood test results and blood pressure readings you enter
- Appointments, side effects, notes, and questions for your specialist
- From version 1.1, if you switch weather on: each day's temperature, humidity, air pressure and conditions — never the place they were for
A question you skip stays unanswered. The app never fills in a blank for you.
Where it is stored
In a database inside the app on your device. The app also writes a daily backup file to your own iCloud Drive, described below, which you can switch off in Settings → Backup. There is no other copy unless you make one.
What leaves your phone
Nothing comes to me, ever. The one thing that leaves your phone without you sending it is the daily backup to your own iCloud Drive, which is on unless you switch it off.
Nothing you record is ever transmitted by the app to anyone else. There is no account to sign in to, no server to sync with, and no third-party code of any kind — no analytics, no crash reporting, no advertising or tracking libraries. Up to and including version 1.0.3 the app contains no networking code at all.
From version 1.1 there is one exception, and it is off unless you switch it on: the weather. If you turn on Settings → Weather, the app asks iOS for your approximate location, rounds it to about 10 km, and sends that — a place and a date, nothing else — to Apple's weather service, to fetch the temperature, humidity and air pressure for the day. Nothing you have recorded goes with it. Your location is never stored: the app keeps the weather, not the place, so neither the app nor your backups hold any record of where you have been. The request goes to Apple under Apple's privacy policy, not to me; I never see it. Switch weather off and the app stops asking for your location and stops fetching. Leave it off and none of this happens at all.
A handful of things can move data off your device. One is the automatic backup, which you can switch off; every other one is something you do:
A backup you export. A single file you share wherever you choose. It goes where you send it.
An automatic backup. Once a day, JointSignal writes a dated backup file to your own iCloud Drive, or to your device if iCloud is not available. Thirty are kept, so a mistake is recoverable. That file sits in your iCloud account under Apple's terms — I have no access to it. You can turn this off in Settings → Backup.
A report you share. When you export a PDF for your specialist and send it by email, message or AirDrop, it carries your health information into whatever you sent it through. That is outside the app's control, so please think about where it is going, particularly over email.
A data export you share (from version 1.1). Report → Export data writes what you recorded as CSV files or one JSON file, for a spreadsheet or an AI assistant. It leaves out Apple Health data, appointments and the names of your clinicians, and it leaves out your free-text notes unless you switch them on. The app hands the file to the iOS share sheet and sends it nowhere itself. If you give it to an AI service, what happens to it next is set by that service's privacy terms, not by this policy — so it is worth reading theirs first.
An email you send me. Settings → Send feedback opens your own email app with a message addressed to [email protected]. It arrives pre-filled with the app's version and build number, your iOS version and your device model — enough to trace a fault to a particular build — and with nothing at all from what you have recorded. No entry, no rating, no joint count, no medicine, no blood result. You write the message and you send it; the app sends nothing itself, and you can delete any of the pre-filled text before you do.
Apple Health
If you allow it, JointSignal reads from Apple Health to show your own activity alongside your symptoms: steps, flights climbed, exercise minutes, walking speed, walking asymmetry, double support time, step length, stair ascent and descent speed, six-minute walk distance, resting heart rate, heart rate variability, sleep, and blood pressure.
The app requests no write access at all. It cannot add to or alter your Health record, by design. Health data is used only to show you your own information: on the Trends screen, and — from version 1.0.1 — on a "Measured by phone" page of the report you export, as medians of a few measures with the number of days each is based on. That page is worked out on your phone at the moment you make the report, and then discarded.
Health data is not copied into your record, it is not included in any backup, and the app never sends it anywhere. If you share an exported report, the Health figures on it go wherever you send them, like everything else on the report. It is never used for advertising or any other purpose.
You can stop the app reading Health at any time, either in the app under Trends, or in iOS Settings → Privacy & Security → Health. Turning it off in the app stops JointSignal reading and drawing that data; only iOS Settings can withdraw the permission itself, and the app says so where it offers the choice.
Reminders
Reminders are scheduled on your device. There is no push server, and no notification is ever sent from anywhere else.
Subscription and payment
If you subscribe, Apple handles the entire transaction. I never see your card details, your billing address, or your Apple Account. Apple provides me with anonymised sales and subscriber totals — numbers, not people — and nothing in that reporting is connected to anything you record in the app.
If your subscription ends, your record remains yours. You keep full access to read and export everything you have entered. Your symptom history is not held hostage to a payment.
Children
JointSignal is not designed for or directed at children.
Your data is yours
Because I hold none of it, there is nothing for me to hand over, correct or delete on your behalf — and no request you need to make. Everything is on your device: you can read it, export it, or remove it entirely by deleting the app. Deleting the app removes the database with it, so export a backup first if you want to keep your history.
One thing is left behind, from version 1.0.3: the date your free first week started, kept in your device's keychain so that deleting and reinstalling the app does not start the week again. It is a date and nothing else, it says nothing about you or your health, and it never leaves the device — it is not synced to iCloud or to your other devices.
If you are in New Zealand, the Privacy Act 2020 applies to me as a New Zealand developer. If you are in the United Kingdom or the European Union, the UK GDPR and GDPR apply. Under all of them, the position is the same: I am not collecting, processing or storing your personal information.
Changes to this policy
If the app ever changes what it does with data, this page changes with it, before the change ships. The date at the top tells you when it was last revised.
Contact
Questions about this policy, or about anything to do with your data: [email protected]
Anything else — problems, suggestions, or a question about how the app works: [email protected]
JointSignal records what you tell it and shows you the patterns. It does not diagnose anything and it is not medical advice. Your rheumatologist does the rest.