Privacy policy

Last updated 25 October 2026. In short: what you make stays on your phone unless you choose to share it; the app goes online only for content updates and for the community features you use; there are no ads, analytics or tracking, and we never sell your data. Blackridge Engineering, LLC, doing business as ZenTrain Studio ("we"), publishes the app and runs its server and the zentrainstudio.com website. Some features named here (comments and posts) are not available yet; what this policy says about them applies once you use them.

What stays on your phone

Your sessions and stages, settings, favourites, the voice's prepared speech, your downloads and your Notate entries are stored only on your device. Notate is never uploaded. The spoken voice is made on your phone; the text you write for it is not sent anywhere. If you sign in, your phone keeps a renewable sign-in key so you stay signed in, never your password.

When the app goes online

Content updates: each time the app opens, and when you come back to it more than six hours after its last check, it asks zentrainstudio.com for new or updated ready-made sessions, Educate articles and sound packs. These requests send nothing about you.
Resonate and share links: opening Resonate loads the list of published sessions. When you publish a session or create a share link, the session (its name, notes, tags, stages and the text of its spoken guidance) is sent to our server with your @handle and shown to others: in Resonate when published, and to anyone who has its link when it is a link only (it is not listed). Unpublishing takes a session out of Resonate; its link keeps working until you delete it. Giving a ✨ Zen records that your account gave it (one per account); playing a session counts a 🎧 play without saying who played it.
Which version you use: every request to our server says which version of the app it comes from (its build number, and whether it is a beta version), with an identifier the app makes at random for this installation (not your phone's own hardware or advertising identifier). When it opens online, the app checks in with our server, so that we know which versions are in use and can tell a version that the beta has ended or that it needs an update; when you are signed in, this is noted with your account. A beta version stops working 180 days after it was made; you can then get the latest version, and everything on your phone stays.
Reports: a report sends what you chose and wrote, and what it is about. A bug report can also send the app's version and your phone's model and Android version, if you leave that box ticked (the app shows them first).
Like every internet request, these reach the server with your device's internet (IP) address and basic technical information (such as the app's web engine version). We use them only to answer the request, to count Zens and plays fairly, and to protect the service from abuse.

Your account and profile

An account is optional for listening and creating; Resonate, sessions others share with you, sharing sessions, giving Zens and sending reports need one. You can sign in with Google, or with your email address and a password, which we ask you to confirm through a link we email you. Signing in is run for us by Google's Firebase Authentication: it keeps your email address, how you sign in and a protected form of your password (we never see or store your password), and it sends the confirmation and password-reset emails. We keep what is needed to run your account: the identifier Firebase gives it, which is a number; your email address, for signing you in, account recovery and support; and the profile you fill in, such as your name, @handle, avatar and a short bio. Your name, @handle, avatar, bio and what you publish are public. Your email address and sign-in identifier are never shown to other users. Signing in with Google also follows Google's own privacy policy. We also note when your account last opened the app (the day and hour), so that we can support accounts and see which are in use.

Looking after accounts

A small ZenTrain Studio team can see accounts to support people and keep the community safe: the profile, the email address, how the account signs in, when it joined and last opened the app, what it has shared, and reports sent by it or about it. It can also see which versions of the app the account uses and its online activity: when the app opened online and what it changed on our server (publishing, sharing, unpublishing, reports, profile changes, agreeing, deleting). Plays and Zens are not part of it. The team can end the beta, or require an update, for everyone or for one account. If an account breaks our Terms we may suspend it, with a reason shown to its owner: it then cannot use Resonate or change anything on our server until we restore it, and what it shared may be hidden meanwhile. On request, we can also delete an account for you. Everything the team does with an account, and every time it looks at one, is written to a record that cannot be changed, so that it can be checked.

The record that you agreed

When you first open the app, you tick that you are 13 or older and that you agree to the Terms of use, this Privacy policy and the Health and safety information. The app keeps a record of that on your phone: the date and time, the versions you agreed to, and an identifier the app makes at random for this installation (it is not your phone's own hardware or advertising identifier). When you have an account, that record is also kept with your account on our server, together with your phone's make, model and Android version and the app's version, so that we can show that you agreed. It is not shown to other users.

Things you post or send

Where the app or zentrainstudio.com lets you comment on sessions, post in Educate or elsewhere in the community, report something or write to us, we store what you post or send, with the date and the account or name it came from. Comments and posts are shown to other users with your public profile. Reports and messages to us are seen only by us, and we use them only to answer you, keep the community safe and enforce our Terms.

Our website

zentrainstudio.com uses no cookies, analytics or tracking scripts and loads nothing from other companies. Like any website, its pages are delivered by our host, which sees your IP address to do so.

What the app does not do

It shows no ads, contains no analytics or tracking code, does not sell or share personal data, does not use your data for advertising, does not record your voice or surroundings, and does not use your location, contacts or photos. Besides internet access, it asks only to show its playback notification, keep playing with the screen off, and vibrate for the Breath Pacer.

Services we use

Our server and website run on Cloudflare, which processes requests and stores our server's data on our behalf. Google's Firebase Authentication runs sign-in for us as described under "Your account and profile", and sends account emails from noreply@zentrainstudio.com. If you sign in with Google, Google tells us the identifier and email address of the account you choose. If you installed the app from an app store, that store may collect crash reports and usage statistics under its own privacy policy and your device's settings. We share data with nobody else, unless the law requires it.

How long we keep things

Published sessions, share links, comments and posts stay until you delete them or your account (unpublishing only takes a session out of Resonate). Your account and profile stay until you delete your account (or ask us to). The app's online activity is kept for 180 days, and removed with your account. The record that you agreed to our terms, and the team's record of what it did with an account, are kept, even after you delete your account, for as long as we may need it to show that you agreed. Reports and support messages are kept only as long as needed to deal with them and with abuse. Request logs on our server are kept only briefly for security. Data on your phone stays until you delete it, clear the app's storage or uninstall the app.

Your choices and rights

You can unpublish your sessions, edit or delete your posts and your profile, clear the voice cache in Settings, delete Notate entries, and remove everything on your phone by uninstalling the app. Deleting your account (in the app, or at zentrainstudio.com/delete-account) removes your profile, your sign-in data, your votes and everything you published or shared. Your @handle is then retired, so nobody else can take it and pretend to be you; reports you sent stay, without your name, and so does the record that you agreed to our terms. Depending on where you live (for example under the GDPR or US state laws) you may have rights to access, correct, copy or delete personal data we hold, or to object to how we use it; contact us to use them.

Children

The app is not directed at children under 13, we do not knowingly collect personal information from them, and they may not create an account. If you believe a child has published personal information or created an account, contact us and we will remove it.

Security

Data on your phone is protected by your phone's own security. Connections to our server use encryption (HTTPS).

Changes and contact

We will show the date of the last update here and tell you in the app about important changes. Contact: ZenTrain Studio · office@zentrainstudio.com