Privacy policy

Last updated: 1 October 2026

1. GENERAL INFORMATION

This Privacy Policy explains what happens to your personal data when you visit and use our website www.zerrromusic.com ("Website"), when you purchase or interact with our services ("Services"), and when you use our AI mastering tool ("ZERRRO Mastering"). Personal data is any information that can be used to identify you directly or indirectly.

We process your personal data in accordance with applicable data protection laws, in particular the General Data Protection Regulation ("GDPR"). We take the protection of your data seriously and implement appropriate technical and organizational measures to protect it.

2. DATA CONTROLLER

The data controller responsible for processing personal data on this Website is:

zerrro
Metzinger Klein Linsenmeier GbR
Höhenweg 23
66133 Saarbrücken
Germany
Email: info@zerrromusic.com

3. ACCESS DATA (SERVER LOG FILES)

When you visit our Website, our hosting infrastructure (Shopify; for ZERRRO Mastering and product reviews: Railway, see Sections 9 and 11) automatically collects and stores access data in server log files. This data may include:

  • Browser type and browser version
  • Operating system used
  • Referrer URL (the previously visited page)
  • Hostname of the accessing device/system
  • Date and time of the request
  • IP address (possibly in anonymized or truncated form)
  • Requested page, amount of data transferred, status information (HTTP status codes), and other technical protocol data

We generally cannot and do not intend to assign this data to a specific person.

Legal basis: Art. 6(1)(f) GDPR (legitimate interests) to ensure the stability, security, and proper functioning of the Website (e.g., troubleshooting, abuse prevention, and system security).

4. COOKIES AND CONSENT MANAGEMENT

We use cookies and similar technologies to enable core website functions and to provide and improve our Services. Cookies are small text files stored on your device.

4.1 Essential (Required) Cookies

Essential cookies are necessary for the Website to function (e.g., shopping cart, login/session management, security). These cookies are processed on the basis of Art. 6(1)(f) GDPR (legitimate interests) and, where applicable, Art. 6(1)(b) GDPR (performance of a contract), because they are required for providing the Services you request. Where processing is based on Art. 6(1)(f) GDPR, you have the right to object at any time for reasons arising from your particular situation.

4.2 Optional Cookies (Marketing / Measurement / Personalization)

Where we use optional cookies (e.g., for marketing or measurement), they are set only if you give consent via our cookie preferences banner/settings (Art. 6(1)(a) GDPR). You can change or withdraw your consent at any time via the cookie preferences on our Website.

You can also configure your browser settings to block or delete cookies. Please note that disabling cookies may limit Website functionality.

5. NEWSLETTER (SHOPIFY EMAIL)

If you subscribe to our newsletter, we will send you emails about products, offers, and updates. Subscription is based on your explicit consent (Art. 6(1)(a) GDPR). We use a double opt-in procedure to verify your subscription.

For sending newsletters we use Shopify Email (a Shopify service). Your email address and any related subscription metadata are processed for the purpose of sending the newsletter and managing subscriptions.

You can withdraw your consent at any time by clicking the unsubscribe link in any newsletter email or by contacting us at info@zerrromusic.com.

6. CONTACT BY EMAIL (CUSTOMER SUPPORT)

If you contact us by email, we will process the personal data you provide (e.g., name, email address, message content) to handle your request.

Legal basis:

  • Art. 6(1)(b) GDPR if your request relates to a contract or pre-contractual measures (e.g., order questions, support for purchased products)
  • Art. 6(1)(f) GDPR for general inquiries and our legitimate interest in responding to messages and maintaining business communication

We keep contact communications only as long as necessary and in accordance with statutory retention periods.

7. CUSTOMER ACCOUNT

If you create a customer account, we process the data necessary for account creation and use (e.g., name, email address, password, order history).

Legal basis: Art. 6(1)(b) GDPR (performance of a contract / provision of account functionality).

8. ONLINE SHOP, ORDERS, AND PAYMENT PROCESSING

To process purchases in our online shop, we process personal data required for the conclusion and performance of the contract (Art. 6(1)(b) GDPR), including:

  • Identity and contact data
  • Order data
  • Payment-related data

Our shop is hosted on Shopify.

8.1 Shopify (Hosting and Store Platform)

We use Shopify as our store platform and hosting provider.

8.2 Payment Methods

We offer in particular:

  • Shopify Payments (including card payments, Apple Pay, Google Pay)
  • PayPal
  • Klarna

Legal basis: Art. 6(1)(b) GDPR.

Payment providers process data under their own responsibility. Please refer to their privacy policies.

8.3 Subscriptions

Where you take out a subscription, your payment method is stored by our payment provider so that recurring charges can be collected. The subscription contract itself is managed by Shopify's subscription functionality. We do not store or have access to complete payment card details.

Legal basis: Art. 6(1)(b) GDPR.

9. ZERRRO MASTERING (AI MASTERING SERVICE)

When you use our AI mastering tool, we process the following data to provide the service.

9.1 Uploaded audio files. Audio files you upload (premasters, reference tracks) and the mastered versions we generate are stored on Cloudflare R2 object storage (Cloudflare, Inc.) in a storage location within the European Union. Processing is necessary to provide the mastering service.
Legal basis: Art. 6(1)(b) GDPR (performance of a contract).

9.2 Hosting of the mastering service. The mastering tool runs on infrastructure provided by Railway Corp. (USA). Server log data as described in Section 3 may be collected.
Legal basis: Art. 6(1)(b) and 6(1)(f) GDPR.

9.3 AI-assisted analysis. Mastering decisions are supported by an AI model provided by Anthropic, PBC (USA). For this purpose, we transmit technical measurement data derived from your audio (e.g., frequency band levels, loudness values) and any text instructions you enter (e.g., "more bass, warm tone"). Your audio files themselves are not transmitted to Anthropic. We do not transmit your name or contact details; the data is not used by Anthropic to train AI models.
Legal basis: Art. 6(1)(b) GDPR (performance of a contract).

9.4 Usage data during the beta phase. While ZERRRO Mastering is in beta, we record how the tool is used — including your chosen settings (genre, platform, character, instructions), the actions you perform in the tool (session log), technical browser information, and the audio files you upload — in order to identify, reproduce, and fix errors and to improve the service. You are informed of this when you first open the tool and asked to agree before continuing.
Legal basis: Art. 6(1)(a) GDPR (consent); for aggregated, non-personal usage statistics also Art. 6(1)(f) GDPR (legitimate interest in improving the service). You may withdraw your consent at any time with effect for the future by ceasing to use the tool and contacting us (see Section 2); this does not affect the lawfulness of processing before withdrawal.

9.5 Feedback. If you submit feedback in the tool (star rating and/or text), we store it together with the context of your session (e.g., chosen settings, session log, related audio files) to evaluate and improve the service.
Legal basis: Art. 6(1)(a) GDPR (consent, given by actively submitting feedback).

9.6 Credits, subscriptions and download history. If you are logged in with your customer account, we store — in connection with your Shopify customer account — your credit balance, your subscription plan and the date through which it is paid, your remaining monthly allowance of masters, and a history of your downloaded masters. This is needed so that we can grant your allowance and so that you can access masters you have already paid for.
Legal basis: Art. 6(1)(b) GDPR.

9.7 Local storage. The tool stores technically necessary data in your browser's local storage (e.g., session state of a running mastering, volume setting, whether you have seen the welcome notice). No third-party tracking takes place through this.
Legal basis: § 25(2) TDDDG / Art. 6(1)(f) GDPR.

9.8 Retention of tool data.

  • Uploads by guest users (without account) are automatically deleted after approximately 24 hours.
  • Files in the library of logged-in users remain stored until you delete them in the tool or request deletion.
  • Previews and unpaid renders are stored only temporarily and are deleted automatically after a few days.
  • Masters you have unlocked are kept for re-download for 12 months from the date of the download and are deleted automatically afterwards, together with the corresponding entry in your library.
  • Beta usage records and feedback are stored only as long as needed for quality assurance during and shortly after the beta phase.

You can request deletion of your data at any time (see Section 15).

10. MARKETING AND ADVERTISING (META / FACEBOOK & INSTAGRAM PIXEL)

If you give consent, we use Meta Pixel for advertising, conversion measurement, and remarketing.

Provider: Meta Platforms Ireland Limited.

Data processed may include:

  • Visited pages, events (e.g., purchases)
  • Device information, identifiers, IP address

Legal basis: Art. 6(1)(a) GDPR (consent).

Meta may transfer data to third countries (e.g., USA). Transfers are based on Standard Contractual Clauses or equivalent safeguards.

We and Meta Platforms Ireland Limited are joint controllers within the meaning of Art. 26 GDPR for data processing via Meta Pixel.

11. PRODUCT REVIEWS

You can review our products directly on the product pages. We run the review system ourselves: reviews are stored in our Shopify store, and a small review service of ours receives and checks new reviews. The review service is hosted by Railway Corp. (USA) on servers in the EU (Amsterdam, Netherlands).

11.1 Data we process. When you submit a review, we process your rating, your name or nickname, your email address, the optional title, your review text, the product you review and the date. Your name or nickname, rating, title, text and the date are published on the product page. Your email address is never published.

11.2 Purchase check and duplicates. We use your email address only to check whether you bought the product in our shop (the review is then marked "Verified buyer") and to make sure that each person reviews a product only once. We do not store your email address with the review; we only store a pseudonymised fingerprint of it (a keyed hash) from which the address cannot be read. We never use it for newsletters or advertising.

11.3 Moderation. We check every review before it is published. We also publish critical reviews and only remove spam, insults or unlawful content.

11.4 Protection against abuse. To protect the review form from spam, the review service uses your IP address to limit the number of submissions. It is held only temporarily in the working memory of the service and is not stored in a database. Railway may also collect server log data as described in Section 3.

11.5 Reviews from before October 2026. Until September 2026 we collected reviews with Judge.me (Judge.me Ltd.). We transferred these reviews to our own system with the information that was already published (name, rating, text and date); email addresses were not transferred. We no longer use Judge.me.

11.6 Storage and deletion. Reviews are stored until you ask us to delete them or we remove them. You can ask us at any time to correct or delete your review at info@zerrromusic.com.

11.7 Legal basis. Publishing your review: Art. 6(1)(a) GDPR (your consent, given by submitting the review; you can withdraw it at any time by asking us to delete the review). Purchase check, duplicate check, moderation and protection against abuse: Art. 6(1)(f) GDPR (our legitimate interest in genuine, trustworthy reviews and in protecting the review form from misuse).

12. RECIPIENTS AND DATA SHARING

We do not sell your personal data. Data is shared only where necessary, e.g.:

  • Shopify (store platform, hosting, email, subscription management)
  • Payment providers
  • Cloudflare, Inc. (audio file storage for ZERRRO Mastering)
  • Railway Corp. (hosting of ZERRRO Mastering and of our review service)
  • Anthropic, PBC (AI analysis for ZERRRO Mastering — technical measurement data and text instructions only)
  • Meta
  • Authorities or legal advisors where required

We have concluded data processing agreements (Art. 28 GDPR) with our processors where required.

13. INTERNATIONAL DATA TRANSFERS

Some providers (e.g., Shopify, Meta, Cloudflare, Railway, Anthropic) are based in or may process data outside the EU/EEA (in particular the USA). Transfers are protected by Standard Contractual Clauses, adequacy decisions (including the EU-U.S. Data Privacy Framework where the provider is certified), or equivalent safeguards. Audio files processed by ZERRRO Mastering are stored in an EU storage location (see Section 9.1).

14. DATA RETENTION

We store personal data only as long as necessary. Legal retention obligations (e.g., tax law) may require storage for up to 10 years.

For customers with a subscription we additionally store, in your customer record, the plan you hold, the date through which it is paid, and your remaining allowance of masters. This is needed to provide the service and is kept for as long as the account exists, subject to statutory retention periods.

Specific retention periods for data from the mastering tool are set out in Section 9.8 and apply in addition to this Section.

15. YOUR RIGHTS

You have the following rights under the GDPR:

  • Right of access (Art. 15)
  • Right to rectification (Art. 16)
  • Right to erasure (Art. 17)
  • Right to restriction (Art. 18)
  • Right to data portability (Art. 20)
  • Right to object (Art. 21)
  • Right to withdraw consent (Art. 7(3))
  • Right to lodge a complaint (Art. 77)

To exercise any of these rights, including deletion of your data, email us at info@zerrromusic.com. We will respond without undue delay and at the latest within one month.

Supervisory authority:

Independent Data Protection Center Saarland
poststelle@datenschutz.saarland.de
https://www.datenschutz.saarland.de

16. SECURITY (SSL/TLS)

We use SSL/TLS encryption to protect transmitted data.

17. CHANGES TO THIS PRIVACY POLICY

We may update this Privacy Policy when necessary. The current version on our Website applies.

— END OF PRIVACY POLICY —