stalwartAll-in-one Mail & Collaboration server. Secure, scalable and fluent in every protocol (IMAP, JMAP, SMTP, CalDAV, CardDAV, WebDAV).

stalwart

An all-in-one mail and collaboration server written in Rust that provides comprehensive protocol support for email, calendaring, contacts, and file storage. Designed with security, scalability, and performance in mind, Stalwart delivers enterprise-grade functionality with modern authentication and encryption standards.

Key Features

• Complete Email Protocols: Full support for JMAP, IMAP4, POP3, and SMTP with extensions including ManageSieve, WebSocket, and Sieve scripting capabilities.
• Collaboration Tools: Built-in CalDAV and CardDAV for calendaring and contacts, WebDAV for file storage, and JMAP-based sharing with fine-grained access controls.
• Advanced Security: Integrated DMARC, DKIM, SPF, and ARC authentication; DANE and MTA-STS transport security; plus built-in spam and phishing protection with LLM-driven analysis.
• Flexible Storage: Pluggable backends supporting RocksDB, FoundationDB, PostgreSQL, MySQL, SQLite, S3, Azure, and Redis with multiple full-text search options.
• Enterprise Features: Distributed virtual queues, message filtering with Sieve scripting, sender reputation monitoring, greylisting, and spam trap capabilities.

Use Cases

• Self-Hosted Email: Organizations wanting complete control over their email infrastructure without relying on third-party providers.
• Unified Communications: Companies deploying a single platform for email, calendaring, contacts, and file sharing across their organization.
• Privacy-Focused Deployments: Environments where data sovereignty and end-to-end encryption are critical requirements.
• High-Volume Mail Processing: Large organizations needing distributed queuing, advanced filtering, and granular throttling controls.

Who Is It For

Stalwart is ideal for system administrators, organizations prioritizing data privacy and control, and enterprises requiring a comprehensive open-source alternative to commercial mail and collaboration platforms. It suits technically sophisticated teams comfortable managing their own infrastructure.