Effective date: 12 September 2026 Version: 1.2
Caffeine Tracker ("the App") is made by Pucl Coffee Roastery and Software Ltd ("Pucl Coffee", "we", "us"), a private limited company registered in England and Wales.
We are the data controller for the personal data described in this policy. This policy explains what data the App handles, where it is stored, and the choices you have. It applies to the iOS app (with the Apple Watch app and widgets), the Android app ("Caffeine Tracker" on Google Play, with its home screen widget), and the optional WHOOP connection.
| Data | Why | Where |
|---|---|---|
| Drinks you log (name, caffeine in mg, time), custom drinks, favourites | To calculate the caffeine in your body and your bedtime cut-off | Local database on your iPhone; a copy of recent entries is shared with your Apple Watch and the App's widgets on your own devices |
| Settings (half-life, bedtime, notification preferences, units) | To personalise the App | Local |
| Apple Health (iOS) or Health Connect (Android) data you allow: dietary caffeine (read/write), sleep, heart rate, resting heart rate, heart rate variability (read) | To show how caffeine relates to your sleep, to include caffeine logged in other apps, and to estimate your personal caffeine half-life | Read from and written to Apple Health / Health Connect on your device only; a short-term cache is kept in the App |
Apple Health and Health Connect data is never transmitted to us or to any third party. Apple's and Google's rules apply: we do not use health data for advertising, and we do not disclose it to data brokers or use it for any purpose other than providing the App's features. You control each data type in the Health app under Sharing (iOS) or in Health Connect (Android).
Notifications (last-drink reminder, morning summary) are scheduled locally on your device.
The WHOOP connection and the Caffeine Coach are optional and only available to Premium subscribers. Nothing in this section applies unless you tap "Connect WHOOP" and sign in to WHOOP, or agree to use the Caffeine Coach.
Anonymous device identifier. When you first use a server feature, the App creates a random identifier and a secret token stored in your iPhone's Keychain. We use it to know which device a WHOOP connection belongs to. It is not linked to your name, email, Apple ID or WHOOP login.
WHOOP authorisation tokens. After you sign in to WHOOP and grant access, WHOOP gives our server tokens that let it read your data. We store them so the App can refresh your data without asking you to sign in again. We request these scopes: recovery, sleep, cycles and basic profile. We do not request workouts or body measurements.
WHOOP metrics. For each day we store: recovery score, heart rate variability, resting heart rate, blood oxygen and skin temperature (where WHOOP provides them), sleep duration and stages, sleep performance, and day strain. We also store your WHOOP user ID, which WHOOP uses to tell us when new data is available.
What we do not store on the server. We never send your caffeine entries, your Apple Health or Health Connect data, or your name or email to the server. The comparison between caffeine and recovery is calculated on your device.
The Caffeine Coach writes a short weekly note and answers your questions using an AI model. Before it is switched on, the App asks for your explicit agreement in a consent screen; the time you agree is recorded on your device.
What is sent. Each request contains only aggregated figures for the current week, calculated on your device: total and average caffeine, number of late-caffeine days and days over your bedtime limit, average time of your last drink, average sleep duration and the sleep difference between late-caffeine and other nights (where Apple Health, Health Connect or WHOOP data is available), average WHOOP recovery, your half-life setting and personal estimate, your bedtime and threshold, the names of your five most-logged drinks with counts, and the change against last week. If you type a question, the question and up to the last ten messages of the current conversation are sent with it. We never send individual drinks, individual nights, heart-rate or HRV records, or any Apple Health or Health Connect record.
Who processes it. Our server in the UK forwards the request to Anthropic, PBC (United States), whose Claude model generates the reply. Anthropic acts as our processor under its commercial terms: it does not use the data to train its models and does not retain it beyond the time needed to produce the reply. Our server does not store the summary, the question, the conversation or the reply; they exist only in memory while the reply is generated. Conversations are kept only on your device while the coach screen is open, and the weekly note is cached on your device.
What we keep. For fair-use limits we count the number of coach requests per device per day (device identifier, day and a counter, no content). These counters are deleted after 7 days.
Withdrawing. Settings → Caffeine Coach → "Withdraw consent and forget notes" stops all further requests and deletes the cached note on your device. "Delete all data" does the same.
Where. Our server and database run on Fly.io infrastructure in London, United Kingdom. Fly.io acts as our processor under a data processing agreement. Encrypted backups may be retained by Fly.io for a limited period.
How long. WHOOP data is kept while the connection is active. When you tap "Disconnect and delete WHOOP data" in Settings, we revoke our access at WHOOP and permanently delete your tokens and all stored WHOOP metrics immediately. "Delete all data" in Settings also deletes the anonymous device record. Connections that have not been used for 12 months are deleted automatically.
Premium subscriptions are sold through the Apple App Store. Apple processes your payment and tells the App whether you have an active subscription. We do not receive your card details, billing address or Apple ID. Apple's privacy policy applies to the purchase.
We do not collect analytics, advertising identifiers, location, contacts, photos, or crash reports through third-party SDKs. If you have opted in to share diagnostics with app developers in iOS Settings, Apple may provide us anonymised crash reports.
We do not sell personal data and do not share it with advertisers or data brokers. We would disclose data only if required by law.
Server data is stored in the United Kingdom. WHOOP is based in the United States; when you connect WHOOP, WHOOP transfers your WHOOP data to our UK server under your authorisation. Caffeine Coach requests are processed by Anthropic in the United States under the UK International Data Transfer Addendum to the EU Standard Contractual Clauses; only aggregated weekly figures and your question are transferred, and nothing is retained.
Under UK data protection law you can ask us to access, correct, delete, or restrict the personal data we hold, object to processing, or request a copy in a portable format. Because the data we hold is tied to an anonymous device identifier, the fastest way to exercise these rights is in the App: Settings → WHOOP → "Disconnect and delete WHOOP data", or Settings → "Delete all data". You can also email info@pucl.co.uk.
You have the right to complain to the Information Commissioner's Office (ICO): ico.org.uk or 0303 123 1113.
The App is not intended for anyone under 16 and we do not knowingly process their data.
Communication between the App and our server uses HTTPS. WHOOP tokens are stored server-side and are never sent to the App. Access to the server and database is restricted to Pucl Coffee staff who need it to run the service.
The App shows relationships in your own logged data. The Caffeine Coach's suggestions are generated by an AI model from those same figures and may be wrong. Neither diagnoses, treats or prevents any condition, and neither is a substitute for advice from a healthcare professional.
We will post any changes here and update the effective date. Material changes will be announced in the App.