Nextcloud Groupware

Last reviewed Sep 13, 2026 · 806 words

Nextcloud Groupware is not a separate product you install. It is the Calendar, Contacts, Mail and Deck apps, enabled from the app store on a Nextcloud instance you already run, and marketed together because together they replace the calendar, address book, webmail and task board of Google Workspace or Microsoft 365. Three of the four are complete replacements. The fourth, Mail, is a client and not a server: it reads an IMAP mailbox that lives somewhere else, and where that mailbox lives is the one decision in this bundle that matters.

Calendar and Contacts are the easy win

Both apps are standards-based front ends over the CalDAV and CardDAV server that ships in Nextcloud core. Enable them, create a calendar, and every client that speaks the protocol syncs: iOS and macOS natively through a CalDAV/CardDAV account, Android through DAVx5 (about 5 euros on Play, free on F-Droid), Thunderbird, Evolution, and anything else that has ever synced with a Google calendar can point at Nextcloud instead. Sharing calendars between family members or a team, public booking links, room and resource booking, and birthday calendars generated from contacts are all there. Importing from Google is an .ics and .vcf export, which Nextcloud ingests without fuss. This part I recommend to anyone with a Nextcloud, with no caveats.

Mail is a webmail client with opinions

The Mail app connects to one or more IMAP and SMTP accounts and gives you a modern webmail: threading, a unified inbox across accounts, tags, snooze, a reasonable compose editor, and integration with Contacts for autocomplete and Calendar for invitations. What it does not do is receive mail. You need an IMAP server, which is either a provider you already pay (Fastmail, Migadu, your domain host) or a mail server you run yourself, and the honest self-hosted email piece is required reading before choosing the second. Stalwart is the modern all-in-one if you go that way. Either way the Mail app is the front door, not the mailbox. Expect it to be slower than a native client on large mailboxes; it caches headers in the Nextcloud database and works hard on a 50,000-message folder.

Deck is a kanban board, and that is all

Deck gives you boards, lists, cards, labels, due dates and assignments, with dated cards showing up in the Calendar app. It is enough for a household or a small team's task board and integrates with Talk and Files for attachments. It is not a project management tool: no Gantt, no time tracking, no reporting. If the requirement is bigger than a board, Vikunja or a dedicated tool fits better, and Deck can stay for the lightweight stuff.

The listing's repository is one app of four

The repository attached to this entry is nextcloud/calendar, which is the Calendar app alone; the star count and the JavaScript language field describe that one app, not the bundle. Mail, Contacts and Deck each live in their own repositories under the same organisation. None of that changes how you install them, which is a click each in the Nextcloud app store or occ app:install calendar and its siblings from the command line.

Making it fast is the same job as making Nextcloud fast

Groupware apps expose the same weaknesses as the rest of Nextcloud: PHP request latency, cron not running, no Redis for locking and caching. Sync clients hit CalDAV every few minutes, so a slow instance shows up as a calendar that takes 10 seconds to open on a phone. The fixes are the standard ones, and making Nextcloud fast lists them in order of payoff: system cron every 5 minutes, Redis, opcache tuned, PHP-FPM with enough workers, and a database that is not SQLite. Sizing at 1 GB is for a couple of users; a family with mail caching and a few calendars is comfortable at 2 GB. The Nextcloud All-in-One container ships with these done, which is the least painful way to get a groupware instance that feels quick.

What I'd do

Enable Calendar and Contacts on day one and move every device to CalDAV and CardDAV; that alone removes the Google account from most people's daily loop. Enable Mail against a paid IMAP provider on your own domain rather than running a mail server, unless you already run one and enjoy it. Use Deck for shared household lists and stop there. Put the instance on Redis and system cron before inviting anyone else to use it. That is a working Google Workspace replacement for a family or a 10-person team for the cost of the Nextcloud you were already running plus about 3 euros a month per mailbox at a provider.