Ok, please let me know! I really need it because like you mentioned you "want to provide 20% of the features supported by expert project management tools that are helpful to 80% of users". And I want to be able to connect other apps that do what you don't. I already tried Holaspirit and I know that I will not find a better tool for managing roles and responsiblities. If it had APIs I would for sure invest in the highest tier, even though I don't need that many users right now.

I'll sure do! We do currently have integrations to project management tools (Asana, Basecamp, Jira, Trello). It allows you to connect a circle to an external tool and create projects from your Holaspirit workspace into your favourite app. You can check the full list of integrations: https://help.holaspirit.com/en/articles/3496520-guide-to-integrations-on-holaspirit
Hope this will help! 🙂

Yes, I saw those integrations and it doesn't really help for me. Are the outgoing Webhooks part of the deal?

Hello Marcel! Yes you'll be able to setup outgoing webhooks for each circle you'll map.
All triggers are listed here: https://help.holaspirit.com/en/articles/3725006-how-to-set-up-outgoing-webhooks
I hope that will work for you! 🙂