Voxstrum
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Privacy Policy

Last updated: 27 July 2026

1. Who we are

Voxstrum is a music learning application developed and operated by Voxstrum Ltd ("we", "us", "our"), United Kingdom. This policy explains how we collect, use and protect your personal data when you use our app.

Voxstrum is used by adults, teenagers and, through the Family plan, by children under 13 with guardian consent. Section 8 explains in detail how we handle children's data — please read it if you are a parent or guardian.

2. Data we collect

We collect the following information when you use Voxstrum:

  • Account data — your display name, email address and, if you add one, a profile photo.
  • Age band and consent records — the age range you declare when you first sign up, and, for under-13 accounts, a record of your guardian's consent (see section 8).
  • Practice data — session duration, lesson progress, streak history and the instruments you learn.
  • AI feedback results — the scores (timing, pitch, accuracy, consistency) and coaching notes generated after a practice session.
  • Audio recordings — only if you use a recording feature. This covers practice recordings, Studio takes and voice dictation (see sections 6 and 7).
  • Compositions — for Platinum users, the songs, lyrics, chords and notes you create in Studio, and any exports you generate.
  • Messages — on the Family plan, messages exchanged between a teacher and their linked student (see sections 9 and 10).
  • Device data — operating system, device model and app version, used for crash reporting only.
  • Push notification tokens — so we can send practice reminders and notifications you have opted into.
  • Purchase history — which subscription you hold and its status. Handled by our payment providers; we never see your card details.
  • Usage analytics — aggregate, anonymous statistics about how the app is used.

We do not collect or store your location — not from anyone, and not on any plan.

Tester sign-ups. Separately from the app, if you volunteer for our Google Play closed test at voxstrum.app we collect the Google account email address you give us, and — only if you choose to fill them in — your first name and the phone or Android version you will be testing on. We use these solely to add you to the Play test group, to email you about the test, and to send your free-access key at launch. We do not add you to a marketing list and we do not share the list with anyone outside the Play testing process. The lawful basis is your consent, which you give with the tick-box on the form; you can withdraw it and have the entry deleted at any time by emailing privacy@voxstrum.app.

3. How we use your data

  • To provide and personalise the Voxstrum service.
  • To track your practice progress, scores and streaks.
  • To generate AI feedback and coaching on your playing (see section 7).
  • To power Platinum Studio features — dictation, the AI co-writer, transcription and export.
  • To let a Family plan teacher support their linked students (see section 9).
  • To screen content for safety and moderate our platform (see section 10).
  • To send notifications you have opted into, and service emails such as account verification.
  • To diagnose crashes and improve app performance.
  • To process subscription payments via our payment partners.

4. Legal bases for processing

Under UK GDPR we rely on the following legal bases:

  • Performance of a contract — to deliver the service you signed up for, including lessons, progress tracking and subscriptions.
  • Consent — for optional features such as push notifications, profile photos, and voice dictation. For users under 13, we rely on consent given by a holder of parental responsibility (UK GDPR Article 8).
  • Legitimate interests — to keep the platform safe (content moderation and safeguarding), to diagnose crashes, and to improve the app. Where children are involved, we treat safeguarding as an overriding interest.
  • Legal obligation — where we must retain or disclose data to comply with the law.

5. Who we share data with

We do not sell your personal data, and we do not share it with anyone for advertising. We share data only with the following service providers, strictly to operate Voxstrum:

  • Firebase and Google Cloud (Google) — authentication, database, file storage, backend functions, analytics, crash reporting and push notifications.
  • Anthropic — provides the AI model behind practice feedback, the Studio lyric co-writer, and message moderation. See section 7 for exactly what is and is not sent.
  • Google Cloud Speech-to-Text — converts your speech to text when you use Platinum voice dictation. This receives your recorded audio.
  • Google Cloud Vision — automatically screens profile photos and composition cover art for unsafe imagery.
  • OpenAI — generates AI cover artwork for Platinum compositions, if you choose to use that feature. This receives the text prompt and artwork description, not your recordings.
  • Resend — sends our service emails, such as account verification and guardian consent requests. This receives the recipient's email address.
  • RevenueCat — manages subscriptions, together with Apple and Google's payment systems.

All of these providers are contractually required to protect your data and may not use it for their own purposes.

6. Audio recordings

Audio you record in Voxstrum is stored in a private, encrypted cloud storage bucket, and it is never used to train AI models. Section 11 sets out exactly what deleting your account does and does not remove.

Your practice recordings are analysed on your own device. When you record a practice session, the pitch and timing analysis happens locally on your phone. Only the resulting numbers — such as a timing score and the notes you were aiming for — are sent onward for AI feedback. Your recording itself is kept in your private cloud storage, and your practice audio is never sent to an AI provider.

There are two exceptions you should know about, and both involve speech:

  • Platinum voice dictation. If you use dictation in Studio, that recording is sent to Google Cloud Speech-to-Text so it can be turned into text. This only happens on Platinum, and only when you actively use the feature.
  • Live speech-to-text in the note editor and Studio uses your device's own built-in speech recogniser. On Android that recogniser is provided by Google, and depending on your device and its settings it may process what you say on the device itself or on Google's servers. This is the same recogniser the rest of your keyboard and apps use.

7. AI features and your data

Voxstrum uses AI in a few places. We think you should know precisely what each one receives:

  • Practice feedback — receives numeric performance metrics and lesson details (for example, which lesson and which notes). It does not receive your audio recording.
  • Studio co-writer and note tools (Platinum) — receive the lyrics or notes you ask us to work on.
  • Voice dictation (Platinum) — sends your dictation audio to Google Cloud Speech-to-Text, as described above.
  • Cover art (Platinum) — sends your artwork prompt to OpenAI.
  • Message and image moderation — screens messages and uploaded images for safety, as described in section 10.

Every AI feature listed above sends its request from our own secure backend, never directly from the app, and our AI keys never touch your device. The one speech feature that does not route through our backend is your device's own built-in recogniser, described in section 6.

8. Children and guardian consent

Voxstrum is used by children, primarily as student seats on the Family plan set up by a parent or teacher. We designed the app around that from the start, and we comply with the UK GDPR (including Article 8) and the US Children's Online Privacy Protection Act (COPPA).

Age declaration. Everyone declares an age band when they first create an account. This happens before any lessons or AI features are available.

Guardian consent for under-13s. If an account is declared as under 13, we require verifiable consent from a parent or guardian before that child can link to a teacher or use AI features. We ask for the guardian's email address, send them a consent request, and hold the account in a restricted state until they approve. This is enforced on our servers, not just in the app.

Additional protections for children and teenagers:

  • AI feedback is blocked entirely for under-13 accounts until a guardian has consented.
  • AI coaching language is automatically softened for users under 18.
  • We never collect location from anyone, on any plan.
  • Streak and engagement mechanics are off for student accounts unless a guardian opts in.
  • A student's data is reachable only by their own linked teacher — never by other users.
  • Messaging is screened, can be revoked at any time, and is audit-logged.
  • If our image screening is unavailable, we fail safe on child accounts and remove the image rather than risk it.

Guardian rights. A parent or guardian can review their child's progress, withdraw consent, and request deletion of their child's data at any time by contacting privacy@voxstrum.app. Withdrawing consent stops AI processing for that child.

We do not show adverts to anyone, and we never use children's data for marketing or profiling.

9. Teachers and student data (Family plan)

The Family plan lets a teacher or parent support up to five students. If you are a student linked to a teacher, that teacher can see:

  • Your practice session history and AI scores.
  • Lesson plans and Play Along tracks they have assigned you, and your progress on them.
  • Messages you exchange with them in the app.
  • Any song you explicitly submit to them for review.

Your teacher cannot see your Studio song projects unless you submit one to them for review. Your private compositions stay private.

Linking is always initiated by an invite code and can be undone. When a link is removed, messaging is revoked immediately.

10. Content moderation and safety

To keep the platform safe — particularly for younger users — we screen certain content automatically:

  • Profile photos and cover art are screened for unsafe imagery using Google Cloud Vision before they appear.
  • Teacher–student messages are screened in two layers: a keyword filter, then an AI classifier, before the message is delivered.
  • Teacher notes and shared tracks are screened before a student can see them.

Content that is blocked, or that a user reports, is recorded in a moderation queue for review. We keep an audit log of child-safety events. These records exist to protect users and may be retained after other data is deleted where we have a legal or safeguarding reason to keep them.

11. Data retention

We retain your account data for as long as your account is active. You can delete your account at any time from Profile → Delete account in the app.

Doing so immediately removes your profile, your practice sessions, your AI feedback history, your notes, your practice recordings, and your sign-in.

Some content you have created is not yet removed automatically by that button: Studio compositions and their exports, Studio recordings and uploads, saved Play Along takes, your ratings and achievements, and your profile photo. If you want everything erased, email privacy@voxstrum.app and we will delete it within 30 days. We are actively working to make one tap remove everything, and we would rather tell you this plainly than imply otherwise.

See how to delete your account for step-by-step instructions, including how to request deletion if you can no longer sign in.

Safeguarding and moderation records (section 10) may be retained longer where we have a legal obligation or a child-protection reason to keep them.

Tester sign-ups (section 2) are kept for the duration of the closed test and for up to 12 months afterwards, so that we can honour the free-access key we promised and answer questions about it. Ask us at privacy@voxstrum.app and we will delete your entry sooner. Deleting a tester entry is separate from deleting a Voxstrum account — tell us if you want both.

12. International transfers

Voxstrum is operated from the United Kingdom, and your files are stored in the United Kingdom and Europe. Some of our service providers — including our backend functions and our AI providers — process data in the United States. Where data leaves the UK or EEA, we rely on appropriate safeguards such as the UK International Data Transfer Agreement or Addendum, and standard contractual clauses.

13. Your rights

Under UK GDPR and applicable law you have the right to:

  • Access a copy of your personal data.
  • Correct inaccurate data.
  • Request deletion of your data.
  • Object to or restrict processing.
  • Withdraw consent at any time, where we rely on consent.
  • Data portability.
  • Complain to the UK Information Commissioner's Office (ICO) at ico.org.uk.

To exercise these rights, contact us at privacy@voxstrum.app.

14. US state privacy rights

This section applies if you live in a US state with a comprehensive privacy law, such as California, Virginia, Colorado, Connecticut or Utah.

We do not sell your personal information, and we do not share it for cross-context behavioural advertising. We show no adverts of any kind, and we have never sold personal information — including that of anyone under 16.

We collect the following categories of personal information:

  • Identifiers — name, email address, account and device identifiers.
  • Commercial information — your subscription and purchase history.
  • Internet or network activity — how you use the app, and crash diagnostics.
  • Audio and electronic information — recordings you choose to make, and the songs, lyrics and messages you create.
  • Inferences — the AI scores and coaching suggestions generated from your practice.

We collect these for the purposes described in section 3, and we disclose them only to the service providers listed in section 5, who are contractually barred from using them for their own purposes.

Depending on your state, you have the right to:

  • Know what personal information we hold about you and how we use it.
  • Request a copy of it, or have it transferred to another service.
  • Correct inaccurate information.
  • Delete your information.
  • Opt out of sale or targeted advertising — though as stated above, we do neither.
  • Not be discriminated against for exercising any of these rights.

To exercise any of these, email privacy@voxstrum.app, or delete your account directly from Profile → Delete account in the app. We will never charge you or reduce your service for asking. If we decline a request, you may appeal by replying to our response.

If you are the parent or guardian of a child under 13 in the United States, section 8 explains your rights under COPPA, including how to review your child's data and withdraw consent.

15. Cookies and tracking

Voxstrum does not use advertising cookies or cross-app tracking, and we show no adverts. We use Firebase Analytics solely for aggregate, anonymous usage statistics to improve the app.

16. Changes to this policy

We may update this policy from time to time. We will notify you of material changes via the app or by email. Continued use of Voxstrum after changes constitutes acceptance.

17. Contact

Questions about this policy?
privacy@voxstrum.app
Voxstrum Ltd, United Kingdom

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