Devcal.dev
devcal.dev
devcal.dev
If you search "calendar api", "calendar service" and similar things on hackernews + rest of the internet, most of the results are frustrating, yet fun.
If you are on the subject, please check it out. you may like it. it's 50% open source atm, not because I'm not aiming to be the next big thing, but the code is embarrassing enough to hide it. But it's fast (enough)...
Collaboration ideas, partnerships, feedback, hateful comments, all welcome. bonus: if anyone has enough free time and manages to hack it, i would love to learn from you + can give some tips or can send a bottle of delicious sardinian wine : )