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

Https://apps.nextcloud.com/apps/tasks seems like it might meet your needs. Source: over 1 year ago

NC Deck (and, very shortly, NC Tasks) to organise my tasks / todos. Source: over 1 year ago

Also, there are probably a few more lightweight and Trello-like systems for Kanban boards:

  - Nextcloud: also has some apps, like https://apps.nextcloud.com/apps/tasks and https://apps.nextcloud.com/apps/deck that, while basic, can be really easy to get started with if you already have Nextcloud.

- Source: Hacker News / almost 2 years ago

I use Nextcloud for managing tasks in the browser, but that requires a Nextcloud server. Https://apps.nextcloud.com/apps/tasks. Source: about 2 years ago