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Last Updated: 08-22-2026 11:03 AM (UTC)

Stalwart Mail

Stalwart replaces the traditional Postfix + Dovecot + SpamAssassin + calendar-server stack with one Rust binary that speaks every standard mail and collaboration protocol natively. JMAP, IMAP4rev2, POP3, SMTP, CalDAV, CardDAV, and WebDAV all run inside the same process — no glue scripts, no sidecar daemons, no version conflicts between components. The pluggable storage architecture lets operators choose RocksDB for single-node deployments, FoundationDB for distributed clusters, PostgreSQL, MySQL/MariaDB, or SQLite for the data store, S3/MinIO/Azure Blob for message blobs, and Elasticsearch or Meilisearch for full-text search, with Redis or the internal engine backing rate limiters and session state. Security features include S/MIME and OpenPGP encryption at rest, automated DKIM key generation with DNS publication, DANE and MTA-STS transport security, automatic ACME TLS provisioning, granular ACLs, rate limiting, and IP banning. The browser-based admin console manages accounts, domains, groups, mailing lists, SMTP queues, DMARC/TLS-RPT/ARF reports, and every configuration object without touching a config file, while the self-service portal at /account gives end users password reset and encryption key management. Multi-tenant support with per-tenant quotas enables hosting-platform deployments, and coordinator-less clustering via Zenoh or NATS scales horizontally by adding nodes. Deploy via Docker or the standalone binary. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. AGPL v3 licensed.

Stalwart Mail
Stalwart Mail
Stalwart Mail
Stalwart Mail
Stalwart Mail

Benefits

  • One Binary Replaces Entire Stack
  • Eliminates separate MTA, IMAP store, spam filter, calendar server, and contact server — a single Rust process handles all protocols with zero inter-service configuration.
  • Memory-Safe and Audited Security
  • Written entirely in Rust with an independent security audit, S/MIME and OpenPGP encryption at rest, automated DKIM rotation, DANE, MTA-STS, and automatic ACME TLS provisioning.
  • Pluggable Storage Architecture
  • Choose RocksDB, PostgreSQL, MySQL, SQLite, or FoundationDB for metadata; S3, Azure Blob, or filesystem for blobs; Elasticsearch or Meilisearch for search — each layer independently configurable.
  • Horizontal Clustering Without Coordinators
  • Scale from single-node to multi-region clusters using coordinator-less Zenoh or NATS synchronization — any node can serve any protocol with no external orchestration required.

Features

  • Complete Protocol Support
  • Native JMAP, IMAP4rev2, POP3, SMTP, CalDAV, CardDAV, and WebDAV — clients connect directly without protocol translation or proxy layers.
  • Built-in Spam Filtering
  • Integrated spam and phishing protection with Sieve filtering, DMARC validation, ARC verification, SPF checking, and configurable content rules — no external SpamAssassin needed.
  • Web Admin Console
  • Browser-based administration at /admin for accounts, domains, queues, reports, storage, and configuration with real-time dashboards and live tracing.
  • Multi-Tenant Hosting
  • Per-tenant quotas, isolated domains, and delegated administration enable mail hosting platform deployments with separate billing and resource limits per organization.
  • Directory Integration
  • Authenticate against internal directory, LDAP, SQL databases, or OAuth providers with automatic account provisioning and role-based access control.