Mailnautica is an open, enterprise-grade mail and collaboration server built for the next decade — faster, simpler, and more secure than Microsoft Exchange, without the complexity tax.
No credit card required · Self-hosted · Open core
Why Mailnautica
Every feature rated against Exchange, Zimbra, Stalwart and the rest.
IMAP4rev2, JMAP, SMTP — all in one stack. Conversation view, snooze, send-later, and split inboxes that actually work.
CalDAV + JMAP calendars, CardDAV contacts, resource booking, free/busy, delegated mailboxes — Exchange-class without the Windows dependency.
1:1 DMs, project channels with threads, presence — without the chaos of Teams. Sane notification defaults baked in.
SPF/DKIM/DMARC/ARC, MTA-STS, DANE, TLS 1.3, built-in anti-spam — not bolt-ons. Memory-safe implementation throughout.
Full REST + gRPC provisioning API. RBAC, delegated admin, audit logs, message trace. Automate everything from day one.
Cmd+K palette across mail, chat, calendar, tasks and settings. One query, every result — the way search should have always worked.
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Space Grotesk — Headlines & Body