Privacy Policy

1. Privacy at a Glance

General Information

The following information provides a simple overview of what happens to your personal data when you visit this website. Personal data is any data by which you can be personally identified.

This privacy policy applies to the website voltplan.app, to our MCP server for AI assistants (mcp.voltplan.app) and to The Busbar (busbar.voltplan.app).

Data Collection on This Website

Who is responsible for data collection on this website?

Data processing on this website is carried out by the website operator. You can find the operator’s contact details in the legal notice (Impressum) of this website.

How do we collect your data?

On the one hand, your data is collected when you provide it to us. This may be, for example, data that you enter in a contact form or when registering for an account.

Other data is collected automatically or with your consent by our IT systems when you visit the website. This is primarily technical data (e.g. internet browser, operating system or time of the page request).

What do we use your data for?

Part of the data is collected to ensure that the website is provided without errors. Other data may be used to analyse your user behaviour. If you create an account, your data is used to provide the services.

What rights do you have regarding your data?

You have the right at any time to receive information free of charge about the origin, recipients and purpose of your stored personal data. You also have the right to request the rectification or erasure of this data. You may contact us at any time regarding this and any other questions on the subject of data protection.

2. Hosting

The content of our website is hosted by the following provider:

Hetzner Online GmbH
Industriestr. 25
91710 Gunzenhausen
Germany

The hosting services we use serve to provide the following services: infrastructure and platform services, computing capacity, storage space and database services, security services and technical maintenance services.

In the course of hosting, Hetzner processes the following data:

• Content data (e.g. entries in online forms)
• Contact data (e.g. e-mail addresses)
• Meta/communication data (e.g. device information, IP addresses)
• Usage data (e.g. web pages visited, interest in content, access times)

The use is based on our legitimate interest in the efficient and secure provision of our online offering pursuant to Art. 6(1)(f) GDPR.

Further information can be found in Hetzner’s privacy policy: https://www.hetzner.com/legal/privacy-policy

3. General Information and Mandatory Disclosures

Data Protection

The operators of these pages take the protection of your personal data very seriously. We treat your personal data confidentially and in accordance with the statutory data protection regulations and this privacy policy.

Information on the Controller

The controller responsible for data processing on this website is:

YuzuHub UG (haftungsbeschränkt)
Stefan Lange-Hegermann
Sedanstr. 3
40217 Düsseldorf
Germany

Phone: +49 211 63556455
E-mail: info@yuzuhub.com

The controller is the natural or legal person who, alone or jointly with others, determines the purposes and means of the processing of personal data.

Storage Period

Unless a more specific storage period has been stated within this privacy policy, your personal data will remain with us until the purpose for the data processing no longer applies. If you assert a legitimate request for erasure or revoke your consent to data processing, your data will be erased unless we have other legally permissible reasons for storing your personal data.

Withdrawal of Your Consent to Data Processing

Many data processing operations are only possible with your express consent. You can withdraw consent you have already given at any time. The lawfulness of the data processing carried out until the withdrawal remains unaffected by the withdrawal.

Right to Data Portability

You have the right to have data that we process automatically on the basis of your consent or in fulfilment of a contract handed over to you or to a third party in a common, machine-readable format.

Information, Erasure and Rectification

Within the framework of the applicable statutory provisions, you have the right at any time to free information about your stored personal data, its origin and recipients and the purpose of the data processing and, where applicable, a right to rectification or erasure of this data.

4. Data Collection on This Website

Cookies and Local Storage

This website uses only technically necessary cookies. Specifically, this concerns a session cookie for login (PocketBase), which is only set if you actively register or log in. Tracking, marketing or analytics cookies are not used.

In addition, your browser uses local storage (localStorage) to store only data that is required for the functions you actively use: your selected language, your own wiring diagram drafts (automatic saving), your personal settings and the acknowledgement of the safety notice. This data does not leave your device and is not transmitted to our servers.

Since we do not use any non-essential cookies or comparable technologies, no consent is required under Art. 5(3) of the ePrivacy Directive and § 25 Abs. 2 TDDDG (German Telecommunications Digital Services Data Protection Act), and you will therefore not see a cookie banner.

Server Log Files

The provider of the pages automatically collects and stores information in so-called server log files, which your browser automatically transmits to us. These are:

• Browser type and browser version
• Operating system used
• Referrer URL
• Host name of the accessing computer
• Time of the server request
• IP address

This data is not combined with other data sources. This data is collected on the basis of Art. 6(1)(f) GDPR.

Registration on This Website

You can register on this website in order to use additional functions on the site. We use the data entered for this purpose only for the use of the respective offering or service for which you have registered.

The mandatory information requested during registration must be provided in full. Otherwise, we will reject the registration.

5. Web Analytics with Umami

This website uses Umami, a privacy-friendly web analytics tool. Umami does not use cookies and does not collect any personal data. Only anonymised data is recorded:

• Pages visited and time spent
• Referrer (which page you came from)
• Browser and operating system (without version)
• Country (based on anonymised IP)
• Screen size

Your IP address is not stored and there is no tracking across multiple websites. The data is hosted on our own servers in Germany. The use is based on Art. 6(1)(f) GDPR (legitimate interest in analysing website usage in order to improve our offering).

6. Use of PocketBase

This website uses PocketBase for data management. The following data is stored:

• User account data (e-mail, encrypted password)
• Created wireframes and electrical diagrams
• Component information

The data is stored on our servers and is not passed on to third parties. The storage is based on Art. 6(1)(b) GDPR for the performance of a contract or pre-contractual measures.

7. MCP Server for AI Assistants

At https://mcp.voltplan.app/mcp we operate a server based on the Model Context Protocol (MCP). Through it, AI assistants such as Claude, ChatGPT or Cursor can create wiring diagrams and perform electrical calculations (e.g. cable cross-section, battery bank, solar system). The same service is also available at https://voltplan.app/.well-known/mcp; this address forwards requests unchanged to mcp.voltplan.app. Neither an account nor an API key is required for its use.

What Data the MCP Server Processes

We do not receive your conversation with the AI assistant. The server only receives the tool calls that your assistant sends to it. These contain technical information about your electrical system, such as voltage, current, cable length and battery capacity, as well as freely chosen names for the system and its components. Please do not include any personal data in this information.

• Tool calls are processed only in memory in order to perform the calculation or generate the wiring diagram. The server operates statelessly: it does not create sessions and stores neither your information nor the results.
• For a wiring diagram, the server transmits the component information to our own interface voltplan.app/api/diagram/generate. It generates the image and likewise stores nothing.
• For each request, our application log records only the time, MCP method, tool name, status code and processing duration; it records no IP addresses and no information from the tool calls. The section “Server Log Files” applies to the IP address that is technically processed when the connection is established.

Usage Statistics

In order to understand which tools are used, the MCP server sends anonymous events to our self-hosted Umami instance (see “Web Analytics with Umami”): connection establishment, retrieval of the tool list and tool calls, each with the tool name, a few coarse inputs (system voltage, output format) and the product name and version of the AI client (e.g. “claude-ai” or “cursor”). The server sends the events itself; your IP address, your conversation and other information from the tool calls are not transmitted in the process.

Links in the Responses

Responses from the MCP server may contain links to voltplan.app marked with the parameter utm_source=mcp, which is evaluated by our cookieless web analytics. Purchase links lead to Amazon via our redirect voltplan.app/api/go. When such a redirect is accessed, we store the product, target URL, source (e.g. “mcp”), browser identifier (user agent), referrer and the country, which we derive locally from your IP address or browser language. We do not store your IP address in the process. As an Amazon Associate we earn from qualifying purchases. Amazon is responsible for data processing on Amazon’s pages.

The same service is available without purchase links and without references to other VoltPlan pages at https://mcp.voltplan.app/mcp-clean. There, responses contain only the link that opens a generated wiring diagram in the VoltPlan editor.

Provider of Your AI Assistant

Your inputs in the AI assistant and the responses of our server are processed by the provider of the assistant (e.g. Anthropic, OpenAI or Cursor) under its own responsibility in accordance with its privacy provisions. The assistant itself decides which tool calls it sends to us; we have no influence on this.

Local Operation (npx or Self-Hosted)

You can also run the MCP server on your own device; the calculations then run locally. For wiring diagrams, your device calls voltplan.app/api/diagram/generate directly, catalogue data on cables and fuses is loaded from base.voltplan.app, and the usage events go directly to our Umami instance. In the process, your IP address is technically processed. Our wiring diagram interface keeps it only in memory in order to limit requests (at most 30 per minute); Umami does not store IP addresses. You can switch off the usage events with the environment variable VOLTPLAN_TELEMETRY=off.

Legal Basis

The processing is based on Art. 6(1)(f) GDPR. Our legitimate interest lies in providing the MCP server securely and reliably, preventing misuse and improving the service on the basis of the usage statistics.

8. Your Rights

You have the following rights with regard to the personal data concerning you:

• Right of access
• Right to rectification or erasure
• Right to restriction of processing
• Right to object to processing
• Right to data portability

You also have the right to lodge a complaint with a data protection supervisory authority about our processing of your personal data.

9. The Busbar (busbar.voltplan.app)

The Busbar is an editorial offering of YuzuHub UG (haftungsbeschränkt), hosted as a static website via GitHub Pages (GitHub Inc., 88 Colin P Kelly Jr St, San Francisco, CA 94107, USA). When the pages are accessed, GitHub processes server log data, including IP addresses, by default. Further information can be found in GitHub’s privacy statement.

The Busbar itself does not set any cookies and does not collect any personal data. Only the colour scheme preference (light/dark) is stored in the browser’s local storage (localStorage). There is no tracking, no web analytics and no integration of external services. Fonts are self-hosted.

10. Changes to Our Privacy Policy

We reserve the right to amend this privacy policy so that it always complies with current legal requirements or in order to reflect changes to our services in the privacy policy, e.g. when introducing new services. The new privacy policy will then apply to your next visit.