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: over 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: almost 3 years ago

To sync with Google Calendar you could use Cron (recently acquired by Notion). Source: 11 months ago

I have been using cron for a while and can vouch for it. Source: about 1 year ago

Cron https://cron.com/ best calendar app I can think of. Source: about 1 year ago

No, not yet. We all speculate and hope Cron integration will solve it since acquisition. Source: about 1 year ago

If they’re both using gmail cron is great, but personally I haven’t really found the need with just 2J’s but the meetings are lighter so that probably comes into play. Source: about 1 year ago