Your privacy.

Who we are

stemless is a scales-practice and homework app for piano students and teachers. It is run by Zdravko Danailov, based in the UK, and is in private beta.

Contact: zdravkodanailov7@gmail.comCopy

What we collect, and why

• Waitlist: your email address, whether you are a teacher or student, and when you joined, so we can invite you.
• Account: Clerk, our sign-in provider, handles your name, email address, profile picture if you have one, and sign-in method, such as email or Google, so you can sign in and use your account.
• Role and teaching name: whether you are a student or teacher and, for teachers, the name students see.
• Grade: the grade you choose in onboarding, to select practice exercises. You can change it in Settings.
• Practice results: each take’s exercise, settings, tempo, scores, timing, duration and counts of correct, wrong, missed and extra notes. These results give you feedback and determine your progress and mastery. Comments from earlier versions may remain with your results.
• Homework: the exercises a teacher sets, dates, notes and which takes were saved for it, so students and teachers can follow the work.
• Connections and invitations: teacher–student links, the names used for them, invitation codes, dates and status, so you can connect and share homework.
• Practice sessions: start, end and last-activity times, to manage sessions and show your practice history.
• Service usage: Records of earlier AI use (request times and amounts), if any, linked to your account. Chat history from earlier versions may also remain.

The notes you play are processed in your browser. Normal practice saves results, not an audio recording or the raw notes you played.

These settings stay on your device in browser storage, including two settings from a hidden feature (panel open, panel width):

• Your Library grade, hand, status and search filters for this browser session.
• Whether finger numbers are shown on the score.
• Whether the exercise introduction is shown.
• Whether the hidden panel was open.
• The hidden panel width.

Why we can use your data

We use account, practice and homework data to provide the service you signed up for (contract).

We use your waitlist details because you asked to join (consent). You can ask us to remove you at any time.

Keeping the service secure and working, including sign-in and abuse limits, is in our legitimate interests.

Who sees what

Your connected teacher sees your name, the homework they set, when you practised it, and only the takes saved for that homework: tempo, score, mistakes and feedback.

They do not see your other Library practice, your browser settings or the grade you chose in your profile. They can see the grades of the exercises they set.

We do not sell your data or show ads.

Services we use

These services process data to provide the app:

• Clerk: sign-in and accounts.
• Convex: our database and backend.
• Vercel: hosting.
• Google: account sign-in if you choose “Continue with Google”.

Our Geist and Instrument Serif fonts are downloaded from Google Fonts at build time and served by stemless through next/font. Your browser does not contact Google to load these fonts.

When you use Listen, your browser downloads piano sounds from gleitz.github.io, hosted by GitHub Pages, and may cache them on your device. That host receives the download request, including your IP address; we do not upload your played notes to it.

We don't currently send your data to any AI service.

We use Vercel Web Analytics to count page visits. It doesn’t use cookies or identify you: it records the page, the site you came from, your country, and your browser and device type. We have not added tracking pixels or advertising trackers. Clerk sets the cookies needed for sign-in. The app also sets a sidebar preference cookie when you open or close the navigation sidebar.

Where your data is stored

Clerk, Convex and Vercel may process data outside the UK, including in the United States. Where they do, we rely on the safeguards they provide, such as standard contractual clauses or the UK Extension to the EU–US Data Privacy Framework.

How long we keep it

Your data stays while your account exists, unless you reset it or ask us to delete it. Deleting your sign-in account does not automatically remove app records. Waitlist entries remain until you ask us to remove them.

You can clear your learning history in Settings → Reset data. Reset is unavailable while you have unfinished homework with a connected teacher: complete it, ask your teacher to cancel it, or disconnect first.

Reset removes these from your learning history:

• All your takes and scores
• Mastered exercises
• Your grade and old onboarding answers
• Practice sessions
• Past homework and its results
• Chat history from earlier versions of the app

It keeps:

• Your account and sign-in
• Student or teacher role
• Your teacher and student connections
• Your teacher keeps a record of homework they set

Past homework is hidden from your history; the teacher’s assignment records remain, with the results removed. Your teaching name, invitations and any existing records of earlier AI use are also kept. Fingering and exercise-intro settings stay on your device; the hidden panel settings are cleared.

To delete your whole account and app data, or your waitlist entry, email zdravkodanailov7@gmail.com. We will do this within 30 days.

Your rights (UK GDPR)

You can ask to access, correct or delete your personal data, object to its use, or receive a portable copy, where these rights apply. Contact zdravkodanailov7@gmail.com.

You can also complain to the Information Commissioner’s Office at ico.org.uk.

Children

Many piano students are young. Students under 13 should use stemless only with a parent’s or teacher’s permission.

A parent can ask us to delete a child’s data at any time by emailing the contact above.

Changes

We will update this page and change the date when our practices change. We will announce material changes by email or in the app.