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, 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.
• 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.

We do not currently use any product analytics or advertising trackers.

• 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 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, and improving reliability.
• 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:

• Stripe — payment processing and billing.
• Backblaze B2 — storage of uploaded audio and derived stems.
• Cloudflare — content delivery network for serving audio and the application.
• Amazon Web Services (SES) — sending transactional email.
• Modal — GPU compute used to run the AI stem separation and audio analysis on your uploads.

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. 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. 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. You must be at least 16 years old (or the minimum age required in your country) to create an account. If we learn that we hold data from a child under this age, we will delete it.

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.