privacy · booking a call

This covers book.kissu.works, where you can book a call with me. Short version: I only get what you type in, it stays on my own server, and nothing here tracks you.

who's behind this

Konstantin BIFERT. For any question about your data, or to use one of the rights below, email catalog.decline628@4wrd.cc.

what I get

Your name, your email address, whatever you write in the notes or questions, the slot you picked and your timezone. That's what I need to actually meet you, nothing more.

where it lives, who sees it

The booking app (Calnode, open source) runs on my own server at Hetzner in Nuremberg, Germany. Your booking sits in a database there, and I'm the only one with an account on it.

emails

Confirmations, reminders and cancellations go out through Lettermint (Lettermint B.V., Netherlands, data kept inside the EU). They see your address and the email itself while delivering it, under a data processing agreement, with open and click tracking off. Their privacy policy.

video calls

When a booking has a video call, it runs on my own server too, straight in your browser: no Zoom, no Google Meet, no Teams. Your browser only ever connects to my server, not even to Google's STUN servers, which most video setups quietly use. Calls aren't recorded, and the video server keeps no logs.

no tracking

No analytics, no third-party scripts, no third-party fonts. The only cookie is a language preference, and only if you use the language switcher. The video room remembers the display name you typed, in your own browser (localStorage). Neither the web server nor the booking app writes your IP address to a log; it's held in memory for about a minute to rate-limit abuse, then forgotten.

legal basis & retention

I process this because you asked me to set up a call, and I can't hold it without your name and a way to reach you (GDPR art. 6(1)(b)). I keep a booking for as long as I need it for the call and my own records, and delete it when you ask. The server takes a daily snapshot that's kept for 14 days, so a deletion reaches those within two weeks.

your rights

Under the GDPR you can ask to access, correct, delete, restrict or object to the processing of your data, and to receive it in a portable form. Email me and I'll sort it out. You can also complain to the Dutch data protection authority, the Autoriteit Persoonsgegevens.

Last updated 4 October 2026.