Assembly Line

Gmail (Google Workspace) vs Stalwart

Gmail (Google Workspace) and Stalwart are both email server software. Gmail (Google Workspace) is a commercial product from Google. Stalwart is open source under a license set out in its repository, with 16k GitHub stars.

Which to pick

Pick Gmail (Google Workspace) when
A business wants reliable hosted email with strong spam filtering and works mostly in the browser.
Pick Stalwart when
You want to self-host email, calendars and contacts in one modern binary instead of assembling Postfix, Dovecot and Rspamd.

Side by side

What it does

Business email on your own domain using Gmail, with spam filtering, shared calendars and admin controls through Google Workspace.

A Rust mail and collaboration server that handles SMTP, IMAP, POP3 and JMAP, plus CalDAV, CardDAV and WebDAV, with built-in spam filtering, DKIM, DMARC and a web admin.

Watch out

Moving away later is a chore, and shared mailboxes and delegation are weaker than in Exchange.

Some features are reserved for the paid Enterprise edition, it only recently reached 1.0, and running any mail server means owning deliverability.

Ready for

Production-ready

Usable

Runs as

Cloud service and mobile app

Self-hosted server

Built with

Not published

Rust, RocksDB and PostgreSQL

Source code

Closed source, sold by Google

Open source, license unclear on GitHub

What the license allows

Closed source: you use it under the maker's terms and cannot change or resell the code.

GitHub could not read the license. Check it in the repository before reusing any code.

How widely known

90k Wikipedia readers a month on phones

16k GitHub stars

How established

Not known

Established: started 3 years ago, latest release v1.0.3.

Other comparisons

More email servers and webmail

Every email server product and project, ranked

Both sides were judged on 2026-11-03 from makers' descriptions, Wikipedia, READMEs and GitHub data. License, age and popularity lines are worked out directly.