Terms of Use
Last updated 24 September 2026
These terms are a contract between you and Luka Kapetanovic, trading as Two Brick Labs, for using the Halcyon app. By creating an account you agree to them. If you do not agree, please do not use Halcyon.
Halcyon is a personal diary. It is not a medical device, it does not give medical advice, and it is not an emergency service. If you are worried about your health, contact your clinician. If you think it is an emergency, contact emergency services now.
1. What Halcyon is, and is not
Halcyon helps you record symptoms, treatments, doses, bleeding, and sleep, see patterns in what you recorded, and organise a summary to bring to your own clinician.
Halcyon does not diagnose, treat, cure, or prevent any condition. It does not tell you whether a treatment is working. It does not tell you to start, stop, skip, or change any medicine or dose. Numbers, trends, and words such as “improved” or “worsened” describe the entries you typed in, nothing more. They do not show that a treatment caused a change.
The articles in Learn, and the fixed safety messages, are general information written from published public guidance such as the NHS, ACOG, and NICE. They have not been reviewed or approved by a doctor or any medical professional, they may not reflect the latest guidance, and they are not advice for you personally. They are not a substitute for a conversation with a qualified clinician who knows your history.
Using Halcyon does not create a clinician–patient relationship with us. No one at Two Brick Labs reviews your logs.
2. Emergencies and safety messages
Halcyon is not monitored and cannot respond to an emergency. Some entries show a fixed safety message with an emergency or crisis-line number for your region. Those messages are general reminders, not an assessment of you. Whether or not a message appears, if you feel unwell or unsafe, contact your clinician or emergency services yourself.
3. Your part
You are responsible for what you enter and for decisions you make about your health. Please talk to your clinician before acting on anything you notice in Halcyon. Check the summary before you share it; you decide who sees it.
You must be 18 or older and able to enter a contract to use Halcyon.
4. Your account
You sign in with Apple or Google. Keep that account secure; you are responsible for activity under it. You can delete your account and all of your logs at any time in Settings.
5. Subscription
Halcyon requires a paid subscription. You buy it through the App Store or Google Play, and their terms and refund rules apply. It renews automatically until you cancel in your store settings. Cancelling stops future charges; it does not refund the current period. If we change the price, the store will ask you before the new price applies.
6. Fair use
Do not try to break into Halcyon, copy or resell it, remove notices, use it to harm others, or use it for anything unlawful. Do not enter another person’s health data without their permission.
7. Your data
Your logs are yours. You give us permission to store and process them only so that Halcyon can work for you, as described in the Privacy policy. Export your data whenever you like from Settings.
8. Availability
We work hard to keep Halcyon running, but we cannot promise it will always be available, synced, or free of errors. Keep your own copy of anything important by exporting it. We may change or retire features. If we ever close Halcyon, we will give you notice and a way to export your data first.
9. No warranties
Halcyon is provided “as is” and “as available”. To the extent the law allows, we make no promises about accuracy, fitness for a particular purpose, or that it meets your needs. This does not remove rights you have as a consumer that cannot be excluded by law.
10. Limits on our liability
Nothing in these terms limits liability that cannot be limited by law, including for death or personal injury caused by our negligence, or for fraud.
Subject to that, we are not liable for any loss that comes from a health decision you or anyone else makes based on Halcyon, from relying on the app instead of a clinician, from data you entered incorrectly, from a missed or late reminder, or from loss of data you did not export. We are not liable for indirect or consequential loss. Our total liability to you for everything arising from Halcyon in any 12-month period is limited to the amount you paid us for Halcyon in that period.
11. Other companies
Apple, Google, RevenueCat, PostHog, and Apple Health are separate services with their own terms. We are not responsible for them.
12. Ending things
You can stop using Halcyon and delete your account at any time. We may suspend or close an account that breaks these terms or that the law requires us to close. Your subscription is governed by the store you bought it from.
13. Changes to these terms
If we change these terms in a way that matters, we will tell you in the app before the change takes effect. Continuing to use Halcyon after that means you accept the new terms.
14. Law
These terms are governed by the law of the Republic of Serbia, and disputes go to the courts of Belgrade. If you live in the EU or UK, you keep any protection your local consumer law gives you, and you may bring a claim in your own country.
15. Contact
Luka Kapetanovic (Two Brick Labs) · support@twobricklabs.com