Context: was looking for a decent service to give me a calendar a little while back but one thing that kept stopping me is there seems to be absolutely no service that just offers you a nice calendar, its only email services that happen to offer a calendar on the side.
I don’t want another email. I have enough, and my current one is tied down to gmail (but I’d prefer if my calendar wasn’t).
I’m sure there must a historical reason for this, but also why is does it still persevere?
One is a scheduling and time management thing, the other a communication system. I don’t need to sign up for a messaging app to have a todo list.
The two aren’t even well integrated smh.
Technically speaking, calendar apps don’t really communicate with each other directly at all. It’s the email systems that talk to the calendars.
As fubo said, there’s no protocol for a calendar function. Protocols are what apps used to talk to each other.
Except… CalDAV exists. It’s built on top of WebDAV and not email. IMAP has the ability to share objects, and some calendar apps use that to share calendars the same way you’d share emails, but there’s an international standard for doing calendars without email.
I personally use a self-hosted NextCloud for calendars and contacts. It integrates into pretty much every app out there, or I can use the web interface or NextCloud apps. Email is only needed for the admin account to send email notifications of someone gets locked out etc.
Those are all protocols for accessing an entire calendar or sharing your whole calendar, not for general-purpose inviting one user to one event.