Privacy policy

Last updated: October 2026

This site is a static website with no analytics, no tracking and no embedded third-party content. What little processing of personal data happens is described here.

Controller

The controller within the meaning of the GDPR is:

Hosting and delivery

The site is delivered by Cloudflare, Inc., 101 Townsend St, San Francisco, CA 94107, USA (object storage and content delivery network). When you open a page, your browser sends the IP address, the requested URL, the time, the referring page and the browser identification to Cloudflare, which processes them to deliver the page and to protect the site against attacks, and keeps them in server logs for a limited time.

The legal basis is my legitimate interest in a fast, reliable and secure delivery of the site (Art. 6 (1) (f) GDPR). Cloudflare is certified under the EU-US Data Privacy Framework and processes the data under standard contractual clauses; see Cloudflare’s privacy policy at https://www.cloudflare.com/privacypolicy/.

Contact form and e-mail

When you write to me through the contact form, your name, e-mail address, the optional company name and your message are used solely to answer your request and, if it comes to that, to prepare a contract. The form sends them to me as an e-mail, which Cloudflare (see above) hands over to my e-mail provider, Proton AG in Switzerland, a country with an adequate level of data protection recognised by the European Commission; the website itself keeps no copy. The legal basis is Art. 6 (1) (b) GDPR (steps prior to a contract) and your consent (Art. 6 (1) (a) GDPR), which you can withdraw at any time with effect for the future.

The data is kept as long as the conversation requires and as long as statutory retention periods demand, and deleted afterwards. The same applies to messages you send by e-mail.

Security check of the contact page

The contact page is protected against spam robots by a security check from Cloudflare. Before the page is shown, Cloudflare checks whether a person or an automated program is asking for it: it evaluates technical data of the request and the browser, such as the IP address and the browser identification, and may run a short test in the browser; now and then it asks you to tick a box. Once you have passed, Cloudflare stores a cookie named cf_clearance in your browser, so that you are not checked again for a while. The cookie serves this check and nothing else.

Storing that cookie is strictly necessary to provide the protected page you asked for (§ 25 (2) no. 2 TDDDG). The processing is based on my legitimate interest in protecting the contact form from spam and abuse (Art. 6 (1) (f) GDPR).

Cookies, analytics and third-party content

Apart from the security check of the contact page, the site sets no cookies, uses no analytics or tracking, and loads no fonts, scripts or other content from third parties. The sites it links to (LinkedIn, GitHub, Wellfound, Telegram, the projects and the clients) have privacy policies of their own.

Your rights

You have the right to information about your personal data (Art. 15 GDPR), to rectification (Art. 16), erasure (Art. 17), restriction of processing (Art. 18), data portability (Art. 20) and to object to processing based on legitimate interests (Art. 21). Consent you have given can be withdrawn at any time. You may also lodge a complaint with a data protection supervisory authority, for example the one of the German state you live in.

Changes

This policy is updated when the site or the law changes. The date at the top says when it was last revised.