Kukkee VS Nextcloud Calendar

I haven't used it much personally, but Kukkee is another option: https://kukkee.com/. Source: about 1 year ago

Maybe you all would find https://kukkee.com useful for creating quick polls. Source: almost 2 years ago

Probably at nextcloud calendar app. Source: about 1 year ago

However, what you're describing seems like any simple Calendar will meet the needs (effectively, here's an event are you coming or not?). Might be overkill, but check out Nextcloud in that case (https://apps.nextcloud.com/apps/calendar). Source: about 1 year ago

I have moved from Google calendar to NextCloud calendar self-host and quite happy with it. I use it with Apple Calendar for creating events, etc. Though sometimes it doesn't sync properly, most of the time, it does the job. The only downside is, I would like to connect my domain/email to the calendar but it is not possible with NextCloud, so it is quite inconvenient if someone tries to invite me. Source: about 1 year ago

If you are a roll-your-own person, you could install and maintain a NextCloud server. See https://apps.nextcloud.com/apps/calendar and https://nextcloud.com/athome/ this is not for the faint of heart. Source: over 2 years ago