Terms of Service
Last updated: 25 August 2026
These terms cover your use of SlumberBrew: the iOS app, and the website at slumberbrew.com including the free web tracker. Both are made by Cael Jones. Using either means you accept these terms.
1. What SlumberBrew is
SlumberBrew estimates how much caffeine is in your system and what will be left at bedtime, based on what you tell it you drank and a published pharmacokinetic model.
The web tracker is free to use and runs entirely in your browser. The iOS app is free to download and use, with an optional subscription (SlumberBrew Pro) for the sleep analysis, full history, and a few other extras. Both use the same model and produce the same figures.
The web tracker is offered as it is, with no guarantee of continued availability. It stores what you log in your browser, so clearing your browser data clears your log, and nothing you log there syncs to the app.
2. What SlumberBrew is not
It is not a medical device, and nothing in it is medical advice. It doesn't diagnose, treat, cure or prevent anything. It isn't a substitute for a doctor, a pharmacist, or a sleep clinic.
The numbers it shows are estimates built on published averages, and they can be wrong for you in both directions:
- Caffeine content varies enormously. The same drink measured across twenty coffee shops varied roughly sixfold. A home drip coffee can be half or double the figure the app uses.
- Caffeine half-life varies several-fold between people. Measured values in healthy adults run from under 3 hours to nearly 10. Oral contraceptives roughly double it. Smoking roughly halves it. Pregnancy, liver conditions and some medications change it further. That's why it's a setting in the app rather than a constant.
Treat the output as a rough guide. If you have a health condition, take medication, are pregnant, or are worried about caffeine or your sleep, talk to a healthcare professional and follow their advice over the app's.
3. Your data
Your log, your ratings and your settings stay on your device. See the Privacy Policy for the detail.
You're responsible for your own backups. If you delete the app, wipe your device, or use Delete everything in Settings, your data is gone and we can't recover it, because we never had a copy.
4. Acceptable use
Don't decompile or reverse engineer the app, try to break the parts of it that enforce purchases (if any exist in your version), or use it in a way that breaks the law. Don't present the app's output as a medical or professional assessment of anyone, including yourself.
5. Subscriptions
The app is free to use. SlumberBrew Pro is an optional subscription: 99p per month or £6.99 per year. Prices are in pounds sterling and may differ in other territories, where Apple sets the local equivalent. Prices may change in future, and any change is announced before it takes effect and never applies to a period you've already paid for.
If your subscription lapses, you keep the free features, including logging, the dial, last call and the caffeine curfew alert. Nothing you have logged is deleted.
Subscriptions are sold and processed by Apple through the App Store, and Apple's terms apply to the transaction. They renew automatically until cancelled. You can manage or cancel in the App Store under your Apple Account, and cancellation takes effect at the end of the current billing period.
We don't process refunds ourselves. Refund requests go to Apple. If you're a consumer in the UK or EU, your statutory cancellation rights still apply, and you exercise them through Apple as the seller.
The web tracker is free and requires no subscription, and so is most of the app.
6. Availability and changes
The app is provided as it is. We may change features, or stop supporting older versions of iOS, in future updates. We'll describe meaningful changes in the release notes.
7. Liability
To the fullest extent the law allows, the app is provided without warranties of any kind, and we aren't liable for any loss arising from your use of it or from decisions you make based on its output.
Nothing in these terms limits liability that can't be limited by law, including liability for death or personal injury caused by negligence, or for fraud. If you're a consumer, you keep all the statutory rights you have under the law of the country you live in, and nothing here overrides them.
8. Governing law
These terms are governed by the law of England and Wales. If you're a consumer living elsewhere, you can still rely on the mandatory consumer protections of your own country.
9. Contact
cmjonesapps90@gmail.com