I started working with Nextcloud way back in 2012 when there were around 10 developers working on ownCloud 2. As of September 2017, Nextcloud is in its 12th edition.
During my time spent in Nextcloud, majority of my work involved working towards incorporating best design practices which is quite hard in an open source project given that design is subjected to a lot more opinion. Today, Nextcloud is one of the most contributed PHP projects on GitHub with a very solid design team.
As a Google Summer of Code Intern at Nextcloud for 2 years (2013, 2014), I co-authored their Calendar and User Management applications while contributing to the overall design. The idea of developing these applications was to have one common design language for Nextcloud core and the apps which was lacking at their time.
Nextcloud Calendar is one of the most succesful Nextcloud applications with over 10 active contributors and 150+ stars on the GitHub repository.
With the spirit of making the calendar consistant with Nextcloud core, we entirely re implemented the left navigation with a strong focus on ease of us while being feature packed. The new calendar sidebar allows users to add or edit calendars, subscribe to external calendars, share calendars or switch calendar views from daily to weekly to monthly. The users can also drag and drop to rearrange calendars making it easier for them to navigate.
While dealing with a single event, a simple popover for displaying event data is not enough, we added a custom highly detailed event sidebar, which allows users to play with the advanced event features like multiple timezones for events, custom repeating events, adding attendees and reminders and many many more features. All these features are added by the community needs and issues raised to us on the issue tracker.
Nextcloud is fully open sourced and used by over a million users who respect data privacy and don't want to put their data on somebody else's servers.
All these projects It would not have been complete without a truly awesome community.