Stalwart Community

Open-source alternative · mapped from 4 paid tools. Fit is not feature parity.

Facts

License

GNU Affero General Public License v3.0 Permissions of this strongest copyleft license are conditioned on making available complete source code of licensed works and modifications, which include larger works using a licensed work, under the same license. Copyright and license notices must be preserved. Contributors provide an express grant of patent rights. When a modified version is used to provide a service over a network, the complete source code of the modified version must be made available. May Commercial useModificationDistributionPatent usePrivate use Must License and copyright noticeState changesDisclose sourceNetwork use is distributionSame license No LiabilityWarranty Summary from GitHub's choosealicense.com

Paid-feature tier C

Self-host

Paid-feature limits3 noted

Enterprise license required for deleted-email restoration and account archiving/un-deletion.
Enterprise-only AI/LLM spam classification and Sieve scripting; standard rule/statistical spam filtering remains Community.
Additional enterprise administration includes multi-tenancy, SCIM provisioning, advanced telemetry and sharded/read-replica storage.

Tier C: Community source is AGPL-3.0-only, with per-file dual licensing and proprietary SEL enterprise sections. C because recovery and AI-assisted mail workflows require Enterprise, beyond administrative extras. Optional first-party managed hosting is announced, not confirmed generally available. License source. Repository: stalwartlabs/stalwart. Self-host: server; hosted offer from the project: no.

Replaces 4 paid tools

Fastmail BusinessEntry price USD 3 / seat / month

Fit:

Email/groupware scope only. Replaces standards-based email/calendar/contact hosting, not Google or Microsoft office apps and vendor automation. Pilot IMAP/CalDAV/CardDAV migration and client behavior; vendor service migration claims do not establish a turnkey Google Workspace or Exchange Online migration. Recovery and AI mail features require Enterprise. Source-account IMAP/export access must be enabled (Zoho Free excludes IMAP); pilot mailbox, calendar and contact transfer separately.

Sources: www.stalw.art, www.stalw.art, www.fastmail.com · checked 2026-10-21
Full comparison: Fastmail Business vs Stalwart Community
Google WorkspaceEntry price USD 7 / seat / month

Fit:

Replaces standards-based email/calendar/contact hosting, not Google or Microsoft office apps and vendor automation. Pilot IMAP/CalDAV/CardDAV migration and client behavior; vendor service migration claims do not establish a turnkey Google Workspace or Exchange Online migration. Recovery and AI mail features require Enterprise.

Sources: www.stalw.art, www.stalw.art, workspace.google.com · checked 2026-10-21
Full comparison: Google Workspace vs Stalwart Community
Microsoft 365Entry price USD 5.40 / seat / month

Fit:

Replaces standards-based email/calendar/contact hosting, not Google or Microsoft office apps and vendor automation. Pilot IMAP/CalDAV/CardDAV migration and client behavior; vendor service migration claims do not establish a turnkey Google Workspace or Exchange Online migration. Recovery and AI mail features require Enterprise.

Sources: www.stalw.art, www.stalw.art, www.microsoft.com · checked 2026-10-21
Full comparison: Microsoft 365 vs Stalwart Community
Zoho MailEntry price Not established

Fit:

Email/groupware scope only. Replaces standards-based email/calendar/contact hosting, not Google or Microsoft office apps and vendor automation. Pilot IMAP/CalDAV/CardDAV migration and client behavior; vendor service migration claims do not establish a turnkey Google Workspace or Exchange Online migration. Recovery and AI mail features require Enterprise. Source-account IMAP/export access must be enabled (Zoho Free excludes IMAP); pilot mailbox, calendar and contact transfer separately.

Sources: www.stalw.art, www.stalw.art, www.zoho.com · checked 2026-10-21
Full comparison: Zoho Mail vs Stalwart Community

Selected by OSSHunt

Stalwart Community is listed as an open-source alternative to Fastmail Business, Google Workspace, Microsoft 365 and Zoho Mail, with partial fit or better. Maintainers can show this in a README; the badge links back to this page.

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[![OSSHunt: replaces 4 paid tools](https://osshunt.com/badge/stalwart.svg)](https://osshunt.com/alternatives/stalwart/)

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