From their page:
As a Founding Contributor, your Gravatar and dofollow link will appear in our sponsors section on all website pages. Plus, you’ll receive a credit worth double your donation toward attending the next edition! Be celebrated as one of the people who made this event possible.
You can contribute as little as EUR 15.
Contribute here: https://checkoutsummit.com/product/checkout-summit-2026-founding-contributor/
