Stalwart Mail Server
Email ServersAn all-in-one mail and collaboration server written in Rust, with JMAP, IMAP, POP3, SMTP, CalDAV, CardDAV and WebDAV, offered in a free Community edition and a paid Enterprise edition.
Open-source alternative to:
What the free edition leaves out
Scroll sideways to view all columns →The free edition is genuinely usable, but some team or enterprise features need a paid plan. “Not confirmed” means the official pages we read did not say, so we do not guess.
| Feature | Free edition | Details | Source |
|---|---|---|---|
| SSO / SAML | Not confirmed | OpenID Connect and OAuth 2.0 are free in Community; SCIM 2.0 provisioning is Enterprise only. SAML is not listed in the comparison table. | Source ↗ |
| Role-based access control | Free | Roles, permissions and ACLs are marked as included in Community (Free) in the comparison table. | Source ↗ |
| Audit logs | Not confirmed | The comparison table lists logging and tracing in both editions and live telemetry, delivery history and alerts as Enterprise only; no audit log item is listed. | Source ↗ |
| Multi-user / teams | Free | Internal directory, LDAP, SQL and OIDC accounts are marked as included in Community (Free). Multi-tenancy with per-tenant quotas and isolation is Enterprise only. | Source ↗ |
| Backups and restore | Not confirmed | Account archiving and restoring deleted emails is Enterprise only, and the Enterprise page says it does not replace backups. No built-in backup tool is listed for either edition. | Source ↗ |
| API access | Free | API keys with labels, IP restrictions and expiration are marked as included in Community (Free). | Source ↗ |
| Support SLA | Paid | Community includes the free support portal. Premium Support is Enterprise only (minimum 150 mailboxes); a dedicated support engineer, a custom SLA and lawful interception are on-demand Enterprise add-ons. | Source ↗ |
Best for
Operators who want one self-hosted server for mail, calendars, contacts and files, and who can live without the Enterprise-only features.
Why choose it over Google Workspace
One memory-safe Rust server covers mail (JMAP, IMAP, POP3, SMTP), CalDAV, CardDAV, WebDAV, spam filtering, DKIM, SPF, DMARC, automatic TLS and clustering, and the comparison table lists nearly all of these in the free Community edition. OIDC, LDAP, two-factor login, roles and API keys are included in Community.
Where it falls short
These are Enterprise only: multi-tenancy and branding, account archiving and un-deletion, AI spam classification and AI Sieve scripting, SCIM provisioning, masked email addresses, live telemetry and alerts, message delivery history, read replicas and sharded storage, and Premium Support. Metrics are listed as limited in Community. The Enterprise edition is under a proprietary license, and the repository carries both licenses.
Open-source alternative to
- Google Workspace — Stalwart can replace hosted business email, calendars and contacts with one server you run, so mailboxes, calendars and contacts stay on your own infrastructure.
- Microsoft 365 — It can replace Exchange Online style email, calendar and contact hosting with a self-run server that clients reach over standard protocols.
Category
Email ServersTopics
Tech stack
Rust
DockerLanguages as reported by GitHub for the repository.
