Privacy Policy

stems.pro (“stems.pro”, “we”, “us”) is a multitrack audio service operated by Nine23 Works LLC that lets musicians upload recordings they own or are licensed to use, separate them into instrument stems, and play them back with real-time mixing and pitch control. This Privacy Policy explains what personal data we collect across our web, iOS, Android, and desktop applications, why we collect it, and the choices you have.

We collect only the data needed to run the service:

• Account data — your email address, display name, optional avatar image URL, and a hashed password. If you sign in with Google, Apple, or Facebook, we store the identifier provided by that provider and the email and name it shares with us. We never receive or store your social-account password.
• Content you upload — audio files you upload and the derived files we generate for you (separated stems, pitched versions, waveform and analysis data), along with metadata such as song titles and setlists you create.
• Usage counters — counts of song splits, storage used, and similar quota metrics tied to your plan.
• Support tickets — messages you send to support and the contact details you include in them.
• Reports and blocks — reports you file about a message, setlist, or user (including a copy of what you reported and your reason), and the list of people you have blocked. A reported user is not told who reported them.
• Payment data — subscriptions and credit packs are billed by Stripe, our payment processor. Your card details are collected and stored by Stripe, not by us. We keep only your Stripe customer reference, plan, and billing status.
• Diagnostics — crash and error reports, performance timings, device characteristics (such as platform, memory, and audio capabilities), and, when an error occurs, a recording of the app screen leading up to it with all text and media masked. These are tied to your account ID (not your email or name) so we can fix problems you run into.
• Product usage — which features you use (for example, that a song was played, a setlist was opened, or a download finished), the screens you visit with any IDs removed from their addresses, and your platform, app version, and language. These events are tied to your account ID (not your email or name) and never include your audio, song titles, or setlist names. You can turn this off at any time in Settings → Preferences → Privacy; we do not collect usage data when you are signed out.

We do not use advertising trackers, we do not use your data to track you across other companies’ apps or websites, and we do not share it with data brokers.

• To provide the service: store your audio, process it into stems on GPU infrastructure, and stream it back to your devices.
• To create and secure your account and authenticate you.
• To process payments and manage subscriptions and credits.
• To send transactional email: account verification, password reset, and billing notices. We do not send marketing email without your consent.
• To respond to support requests.
• To understand which features are used and improve the product.
• To enforce quotas, prevent abuse, and keep the service secure.
• To comply with legal obligations.

Where the EU or UK General Data Protection Regulation applies, we rely on the following legal bases:

• Performance of a contract — providing the service you signed up for, including storing and processing your audio and handling billing.
• Legitimate interests — securing the service, preventing fraud and abuse, improving reliability, and understanding how the product is used so we can improve it (you can object to the latter with the in-app usage analytics switch).
• Legal obligation — retaining billing records and responding to lawful requests.
• Consent — for anything optional, which you can withdraw at any time.

We do not sell your personal data. We share it only with the service providers that make stems.pro work, each acting as a processor on our behalf:

• Payment processor (Stripe) — payment processing and billing.
• Cloud storage provider — storage of uploaded audio and derived stems.
• Content delivery network — serving audio and the application to your device.
• Cloud email delivery provider — sending transactional email.
• Cloud GPU compute provider — running the AI stem separation and audio analysis on your uploads.
• Error monitoring provider (Sentry) — receiving the diagnostics described in section 2.
• Product analytics provider (PostHog) — receiving the product usage data described in section 2.

If you subscribe after arriving through a creator’s referral link or promo code, we notify that creator of the conversion. The notification includes your display name, a partially masked version of your email address (never the full address), and the plan you chose — enough for the creator to recognize the referral, not to contact you.

We may also disclose data if required by law, or in connection with a merger, acquisition, or sale of assets, in which case this policy will continue to apply to your data.

Our infrastructure is based in the United States. If you use the service from outside the US (including the EEA, UK, or Switzerland), your data will be transferred to and processed in the US. Where required, we rely on appropriate safeguards for these transfers, such as the European Commission’s Standard Contractual Clauses with our processors.

We keep your account data and content for as long as your account is active. When you delete individual songs or stems, they are removed from active storage. When you delete your account, we delete your personal data and content within 30 days, except where we must keep records longer for legal reasons (for example, billing and tax records) or in encrypted backups that expire on a rolling schedule.

If your account was referred through our affiliate program, we retain a pseudonymized referral record after account deletion — a keyed hash of your email, your payment-provider customer reference, and the commission entries derived from your payments. This record cannot be used to contact you; we keep it because affiliate commissions, refunds, and fraud checks can arise months after a deletion. See also section 9 on how referral codes are captured.

You can, at any time:

• Access and export your data, including downloading your uploaded audio and derived stems.
• Rectify your account details (email, display name) in Settings.
• Delete your account and all associated content from the Settings page in the app (Settings → Profile → Delete account); see Delete your account for the full steps. If you cannot access your account, email support@stems.pro and we will process the deletion for you.
• Object to or restrict certain processing, and withdraw consent where processing is based on consent.

If you are in the EEA or UK, you also have the right to lodge a complaint with your local data protection authority.

We use browser storage (cookies and localStorage) only to keep you signed in and to remember app preferences such as your mixer settings. While you are signed in and have not turned off usage analytics, our analytics provider also keeps a random identifier in localStorage (no cookies) so your product usage events can be grouped. We do not use advertising cookies or third-party tracking. Clearing your browser storage signs you out but does not delete your account.

If you arrive through a creator’s referral link (a ?ref= address), we store that referral code in your browser’s localStorage for up to 60 days so the creator can be credited if you sign up. It is a single value, set by us (never a third party), used only at registration, and removed when you sign in or sign up.

All traffic is encrypted in transit with TLS. Passwords are stored hashed, never in plain text. Access to production systems is restricted and audited. No online service can guarantee absolute security, but if we learn of a breach affecting your data we will notify you as required by applicable law.

stems.pro is not directed at children under 13. You must be at least 13 years old to create an account, or older if your country sets a higher age for consenting to the processing of personal data (for example, 16 in some EU countries). Users under 18 need the permission of a parent or legal guardian. We do not knowingly collect personal data from children below these ages; if we learn that we have, we will delete it. If you believe a child has given us personal data, contact us at support@stems.pro.

We may update this policy as the service evolves. If we make material changes we will notify you by email or an in-app notice before the changes take effect. The “Last updated” date at the top of this page shows the current revision.

Questions about privacy or your data? Email support@stems.pro. For legal inquiries, contact legal@stems.pro. See also our Terms of Service and Copyright Policy.