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Metis Suite vs Roundcube
Roundcube is the long-running open-source webmail client for IMAP servers, written in PHP and run by Nextcloud GmbH, with calendars, files and AI only through third-party plugins. Metis Suite is also self-hosted and open source, and adds Gmail, Microsoft 365 and Zoho through their APIs, calendars and drives from several providers, a built-in AI agent with approvals, workflows and an MCP server.
Roundcube facts checked on October 21, 2026
| Feature | Metis Suite | Roundcube |
|---|---|---|
| License | Open source, AGPL-3.0-or-later Source | Open source, GPL-3.0-or-later Source |
| Self-hosting | Yes, with Docker Compose on your own Linux server, or run for you on Metis Cloud Source | Self-hosted only: PHP 8.1+, a database and an existing IMAP/SMTP server Source |
| Mail accounts | Gmail, Microsoft 365 and Outlook.com, Zoho Mail, and IMAP servers the instance owner adds Source | Any IMAP server the operator configures, with optional OAuth for Gmail and Microsoft; one account per login without plugins Source |
| Calendar | Google Calendar, Outlook, Zoho Calendar and CalDAV in one view, with editing and RSVPs Source | None built in; third-party plugins Source |
| Files and drives | Google Drive, OneDrive, S3, WebDAV, FTP and SFTP in one explorer, with previews Source | None built in; third-party plugins Source |
| AI assistant | One agent across mail, calendars and drives; sending, deleting and every calendar, drive or workflow change waits for your approval Source | None in core; third-party plugins help write and summarize Source |
| AI model | Bring your own: OpenAI, Anthropic or any OpenAI-compatible endpoint, including one you run yourself Source | Not in core; some plugins take any OpenAI-compatible endpoint Source |
| MCP | Built-in MCP server with OAuth for Claude, Cursor, Codex and VS Code; sending and deleting stay off until you enable them Source | None Source |
| Automation | Visual workflows on new mail, a schedule, a manual run or before a send, with AI Ask and Branch steps Source | Server-side Sieve filters through the bundled managesieve plugin Source |
| Apps | Web; desktop apps for macOS, Windows and Linux; an Android app; no iPhone app Source | Web only, with a responsive skin for phones Source |
| Price | Free to self-host; Metis Cloud from $10 a month billed yearly, or $12 monthly, per instance | Free; enterprise support from Nextcloud GmbH by quote Source |
Choose Roundcube if
You run your own IMAP server and want a mature PHP webmail with Sieve filters and a large plugin catalog.
Choose Metis Suite if
Your accounts are spread across Google, Microsoft, Zoho and your own servers, or you want AI, workflows and MCP built in.
Roundcube is made by The Roundcube project, run by Nextcloud GmbH. Every fact about it on this page comes from its own website, documentation or source code, as linked, and was checked on October 21, 2026. Products change: if something here is out of date, write to contact@astraqcyberdefence.com and we will correct it. All trademarks belong to their owners.