Jazz in Amsterdam was created by Ties Laarakker, who receives financial support from New Amsterdam Jazz for maintaining the website.
An API is available at https://jazzin.amsterdam/api. Part of the source code can be viewed at https://github.com/Tiesselaar/jina.
You can support the project by making a donation.
Disclaimer: content on this website is automatically collected, unedited, unreviewed and certainly contains mistakes. References to official listings are provided as much as possible, so check those.