Open source
Read the code.
Atomic Booking is built on cal.diy, an AGPL-licensed fork of the open-source Cal.com booking platform. We replaced the American payment processors with Mollie and GoCardless, deployed it in Frankfurt, and ship the code back. Here it is.
GitHub
github.com/straun-group/atomic-booking
The repository is public and updated continuously. You can read every commit, every payment flow, and every database query that handles customer data.
What AGPL means for you
The AGPL-3.0 licence is the strongest copyleft licence in common use. It says: anyone running the software as a network service must make their modifications available to users.
We modified cal.diy to remove Stripe and PayPal, integrate Mollie and GoCardless, host on Hetzner, and add the four-tier billing system. Every one of those modifications is in our public repository.
If you want to fork our work and run your own version on your own server, you can. We'd appreciate attribution but we won't enforce a brand requirement — just don't call it Atomic Booking.
Trademarks
"Atomic Booking" and "Atomic Engine" are registered trademarks of Atomic Engine Ltd. The atom logo is also trademarked. The code is open source; the brand is not. If you fork the code, please use a different name.
Why this matters
Closed-source booking platforms ask you to trust their privacy policy. We ask you to read our code instead. If we ever route data somewhere we shouldn't, you'll see the commit before we ship the change.