Mail, domains & deliverability
How this is scored
How well the mailbox itself works: custom domains and their DNS set-up, aliases, catch-all, shared and functional mailboxes, distribution lists, mailbox and attachment size limits, IMAP, POP3, SMTP and Exchange ActiveSync or MAPI for Outlook, web and mobile apps, spam and malware filtering, SPF, DKIM, DMARC and MTA-STS, out-of-office and server-side rules, send limits, and the delivery reputation of the sending infrastructure. A self-hosted groupware is judged on the mail server it ships; a suite whose mail app is only a client for another server scores at the level of that client.
0 — No mailbox at all; a product that only sends transactional mail or only reads another provider's mail without a server of its own or a documented one to pair it with.
3 — Mailboxes on a custom domain with IMAP and SMTP and a webmail; aliases, shared mailboxes, filtering and DKIM or DMARC are basic or not described.
5 — Several custom domains with a documented DNS set-up, aliases and distribution lists, shared or functional mailboxes, IMAP and SMTP plus mobile apps, spam and malware filtering, SPF and DKIM signing, mailbox size per plan stated, server-side rules and out-of-office replies.
8 — Exchange ActiveSync or native Outlook (MAPI) support, DMARC reporting and MTA-STS or DANE, catch-all and plus addressing, delegated access and send-as, quarantine an admin can review, send and attachment limits stated, and the deliverability of the outbound infrastructure documented.
10 — A mail platform a large organisation runs on: every protocol above with feature parity stated per client, inbound and outbound gateways configurable, journaling, DANE and MTA-STS enforced, delivery monitoring and bounce analysis for admins, and mail flow documented end to end.
The Skeptic
The groupware pages say it plainly: Nextcloud Mail is "a client for IMAP-infrastructure; Nextcloud does not include a mail server," and shared mailboxes "you would have to set up... on your mail server." The client itself is respectable — S/MIME, OpenPGP via Mailvelope, mailbox sharing through IMAP ACLs, multiple accounts, automatic phishing detection — but every deliverability question I ask, from custom-domain DNS to DKIM, DMARC, spam filtering, send limits and outbound reputation, lands on a server the vendor neither ships nor documents here; the only server pairing visible is Dovecot Pro and Stalwart turning up as licensed products in the data processing list. 2 12 13 14