Privacy Policy

1. Who operates this site

BillSplitter (https://billsplitter.ch) is operated by Siempi AG, a company registered in the Canton of Zug, Switzerland. The data controller in the sense of the GDPR and Swiss DSG (FADP) is:

Siempi AG
Mauro Miotti
Birkenstrasse 47
CH-6343 Rotkreuz, Switzerland
Email: billsplitter@siempi.ch

2. What we process and why

BillSplitter is a calculator. It runs in your browser and the invoice amounts, dates, and split configurations you enter are not transmitted to our servers. The following categories of personal data are processed:

• Technical logs and analytics: When you visit the site, Google Analytics 4 records pageviews, device type, language, approximate location (country level), and session duration, only if you consent. Legal basis: Art. 6(1)(a) GDPR / Art. 31 DSG (consent).
• Contact form submissions: If you write to us via the contact form or directly email billsplitter@siempi.ch, we process your name, email address, and message content to respond to your request. Legal basis: Art. 6(1)(b) GDPR (contract/pre-contract) and Art. 6(1)(f) GDPR (legitimate interest in responding).
• Server logs: Firebase App Hosting (Google Ireland / EU) records standard HTTP access logs (IP address, user agent, request path, timestamp) for security and operational monitoring. Legal basis: Art. 6(1)(f) GDPR (legitimate interest in secure operation). Retention: 30 days.

3. Cookies and local storage

We use the following cookies and browser-storage keys:

In addition, the following browser local-storage keys are used purely on your device and are never sent to us: theme (dark/light mode preference), invoiceFormDataCache (draft of the calculator form so you don't lose input on reload), billingperiodallocator-language (cached language choice).

You can change your cookie preferences at any time using the Privacy Settings link in the footer, or by clearing the siempiBillSplitterConsent cookie in your browser.

4. Third-party services

We use the following processors. Each has their own privacy policy:

• Google Analytics 4 — Google Ireland Limited (EU) and Google LLC (US). Used for anonymous pageview analytics, only with your consent. See Google's Privacy Policy.
• Resend — Resend, Inc. (US). Used as the email delivery service for feedback you submit via the contact form. See Resend's Privacy Policy.
• Firebase App Hosting — Google Ireland Limited (EU), region europe-west4 (Netherlands). Hosts the site and processes standard access logs. See Firebase Privacy Information.

5. International transfers

Google Analytics and Resend are US-based. Personal data transferred to these services may be processed in the United States. Transfers are safeguarded by Standard Contractual Clauses (SCCs) pursuant to Art. 46 GDPR. Google is certified under the EU-US Data Privacy Framework.

[LAWYER REVIEW] The exact safeguards for Resend may warrant review if your processing volume is material.

6. Your rights

Under the GDPR (Art. 15–22) and the Swiss FADP, you have the right to:

• Access the personal data we hold about you
• Request correction of inaccurate data
• Request deletion (right to be forgotten), subject to retention obligations
• Restrict processing or object to it
• Receive your data in a portable format
• Withdraw consent at any time (without affecting lawfulness of prior processing)
• Lodge a complaint with a supervisory authority — in Switzerland this is the Federal Data Protection and Information Commissioner (FDPIC); in the EU, your national data protection authority.

To exercise any of these rights, contact us at billsplitter@siempi.ch or via the contact form. We respond within 30 days.

7. Retention

• Analytics data (Google Analytics): 14 months, then deleted automatically.
• Feedback emails: retained for as long as necessary to handle the request, typically deleted within 12 months.
• Server access logs: 30 days.
• Cookie consent record: 150 days (then the banner re-prompts).

8. Security

All traffic is served over HTTPS with HSTS enabled. The site uses a strict Content Security Policy, X-Frame-Options, and modern browser-security headers. Feedback form submissions are rate-limited per IP and transmitted only over encrypted channels.

9. Changes to this policy

We may update this policy to reflect changes in services or regulation. The "Last updated" date at the top of the page reflects the current revision. Material changes will be announced via a banner on the site before taking effect.

10. Contact

For any privacy-related question, request, or complaint, email billsplitter@siempi.ch. Company details are in our Imprint.