Privacy Policy

Effective 14 September 2026. Version 1.1. Covers cookies too, because there are none.

Data controller: Optimum Paweł Kowalski, ul. Pozytywistów 4/4, 20-639 Lublin, Poland

Tax ID (NIP): 712-031-17-46

Contact: [email protected]

The short version

1. What we process and why

DataPurposeWhere it livesHow long
The audio file you uploadTo separate it into stemsOur backend server and the GPU provider that performs the separationOn the backend until the separation finishes and for a short time after; the provider keeps it only for the duration of the job
The separated stemsTo play them in your browser and to serve the same song again without re-separating itCloud file storage, at an address derived from the file's content hash, not from youUp to 30 days after they were created
A mix you send to CountInTo hand the file over to countin.band, which runs on another domainOur backend24 hours, then deleted
A hash of your IP address and browser typeTo count separations per person for the daily limitBackend memory, never on disk24 hours
Server logs (IP address, request, time)To keep the Service running and to stop abuseOur hosting providersPer those providers' short retention, typically days

Legal basis: performance of the Service you asked for (Art. 6(1)(b) GDPR) for the files and the hand-off; our legitimate interest in running a fair, secure service (Art. 6(1)(f)) for the daily limit and the logs.

2. What stays in your browser

Your library (songs, stems, exported mixes and your mixer settings) is stored in your browser's own storage (IndexedDB and localStorage) on your device. It never leaves your device unless you upload a new file, export a mix, or send one to CountIn. Clearing site data removes it; Safari on iPhone may remove it after a period of not using the site. We cannot see it and cannot restore it.

3. Cookies

StemPlayer sets no cookies and loads no analytics or advertising scripts. The browser storage described above is used only to make the app work (remembering your library and whether you prefer the simple or the full mixer), which is why there is no cookie banner. Fonts are loaded from Google Fonts, which sees your IP address when the font file is requested.

4. Who else processes data

We use service providers who process data only on our instructions and under data processing agreements:

We will tell you the name of any provider on request at [email protected]. Transfers outside the European Economic Area rely on the EU-US Data Privacy Framework or on the European Commission's standard contractual clauses; you can ask us for details of the safeguards. We do not sell data and do not share it for advertising.

5. Your rights

Under the GDPR you can ask for access to, correction or deletion of personal data we hold, object to processing based on legitimate interest, and complain to a supervisory authority (in Poland: Prezes Urzędu Ochrony Danych Osobowych). Since we have no account and cannot tie a stored stem to a person, a deletion request should include the file or its name and the approximate date of upload. Write to [email protected].

6. Children

The Service is not directed at children under 16, and we do not knowingly process their data.

7. Changes

We may update this policy; the current version and its effective date are always at this address.