Privacy Policy

1. Controller

The controller responsible for data processing on this site under the GDPR is:

2. Overview

This site is a static, client-side web application hosted on GitHub Pages. Data processing is limited to:

• Server-side access data (via GitHub Pages infrastructure)
• Web analytics via Google Analytics
• CDN requests to jsDelivr for third-party libraries

There is no user registration, no form submissions, and no marketing cookies.

3. Hosting (GitHub Pages)

The site is hosted on GitHub Pages, a service provided by GitHub, Inc. (88 Colin P Kelly Jr St, San Francisco, CA 94107, USA), a subsidiary of Microsoft Corporation. When you visit the site, GitHub necessarily processes:

• IP address of your device
• Date and time of the request
• URL requested and HTTP status
• User agent (browser, operating system)
• Referrer

Legal basis: Art. 6(1)(f) GDPR (legitimate interest in operating the site securely and reliably).
Transfers: GitHub, Inc. is certified under the EU-U.S. Data Privacy Framework.

For details see the GitHub Privacy Statement.

4. Web analytics (Google Analytics)

This site uses Google Analytics 4, a web analytics service provided by Google Ireland Limited (Gordon House, Barrow Street, Dublin 4, Ireland). Google Analytics uses cookies and similar technologies to collect and analyse information about the use of this site, including:

• Pages visited and time spent
• Referral source
• Approximate geographic location (derived from IP address)
• Device and browser information
• Interaction events (clicks, scrolls)

IP anonymisation

Google Analytics 4 does not log or store full IP addresses. Google uses the IP address for geolocation and network metadata during collection, then discards it.

Cookies

Google Analytics sets first-party cookies (notably _ga and _ga_*) to distinguish unique visitors. These cookies are stored for up to 2 years.

Legal basis

Art. 6(1)(f) GDPR (legitimate interest in understanding how the site is used to improve it). We acknowledge that some data protection authorities consider consent (Art. 6(1)(a) GDPR) the appropriate basis for analytics; if you do not wish to be tracked, you may use a browser extension such as Google Analytics Opt-out or enable your browser's "Do Not Track" setting.

Transfers

Data may be transferred to Google LLC in the USA. Google Ireland Limited relies on the EU-U.S. Data Privacy Framework and EU Standard Contractual Clauses (Art. 46(2)(c) GDPR) for such transfers.

For details see the Google Privacy Policy.

5. CDN (jsDelivr)

Third-party JavaScript libraries (Chart.js, Pako) are loaded from jsDelivr, a free, open-source CDN operated by Prospect One Sp. z o.o. (Poland, EU). When your browser fetches these files, jsDelivr necessarily receives your IP address and request metadata.

• Purpose: deliver JavaScript libraries efficiently.
• Legal basis: Art. 6(1)(f) GDPR (legitimate interest in a performant site).

See the jsDelivr Privacy Policy.

6. Cookies

This site itself sets no first-party cookies. However, Google Analytics sets the following cookies:

• _ga — distinguishes unique visitors (expires after 2 years)
• _ga_<ID> — maintains session state (expires after 2 years)

GitHub Pages and jsDelivr may set strictly necessary, short-lived cookies as part of their infrastructure. These are covered by § 25(2)(2) TDDDG (strictly necessary for the telemedia service explicitly requested by the user).

7. Local data processing

The simulator processes all cost data entirely in your browser. Usage data you paste or load via URL parameters stays on your device and is never transmitted to any server.

8. External links

This site links to external services (GitHub, Buy Me a Coffee, AWS documentation). Following a link transmits data (such as your IP and referrer) to the respective provider. The operator has no control over data processing by those providers; please consult their privacy policies.

9. Your rights

Under the GDPR you have the following rights:

• Access to the data held about you (Art. 15)
• Rectification of inaccurate data (Art. 16)
• Erasure (Art. 17)
• Restriction of processing (Art. 18)
• Objection to processing (Art. 21)
• Data portability (Art. 20)
• Withdrawal of consent at any time (Art. 7(3))

An informal email to the controller above is sufficient to exercise any of these rights.

10. Right to complain

You have the right to lodge a complaint with a data protection supervisory authority if you believe that the processing of your personal data infringes the GDPR (Art. 77). The competent authority for the controller's place of residence is:

Berliner Beauftragte für Datenschutz und Informationsfreiheit (BlnBDI), Friedrichstr. 219, 10969 Berlin, www.datenschutz-berlin.de

11. No automated decision-making

No automated decision-making or profiling under Art. 22 GDPR takes place.

12. Changes to this policy

This policy may be updated if the legal framework changes or if new features are introduced on the site. The current version is always available at this URL.

Last updated: April 2026