Stalwart provides mail and collaboration server software supporting IMAP, JMAP, SMTP, CalDAV, CardDAV, and WebDAV.
Open source
5 alternativesStalwart
Run email, calendar, contact, and file services with Stalwart, an open-source collaboration server.
About Stalwart
Stalwart is a mail and collaboration server intended to run email, calendars, contacts, and shared files on one server. It supports JMAP, IMAP, POP3, SMTP, CalDAV, CardDAV, and WebDAV, so existing clients can connect without changes. The homepage describes the server as built with built-in spam and phishing filtering, automatic TLS certificate provisioning, and automated DKIM key handling. It can run on a single node or as a cluster across regions, and it can use existing storage, search, directory, and DNS services as backends.
The homepage describes Stalwart as open source, but the directory record does not mark it as open source. Pricing is not known from the source. Some features depend on optional choices: mailboxes can be encrypted at rest with a user's S/MIME or OpenPGP key, and the storage, search, and DNS integrations are chosen by the operator.
Key features
- Single server for email, calendars, contacts, and shared files
- Mail and collaboration access over JMAP, IMAP, POP3, SMTP, and DAV protocols
- Built-in spam and phishing filtering applied before messages reach mailboxes
- Optional encryption of mailboxes at rest with S/MIME or OpenPGP
- Automatic TLS certificate provisioning and renewal over ACME
- Pluggable storage and search backends, including PostgreSQL, MySQL, and S3
Best for: Administrators who want to self-host email, calendar, contact, and file services on one server rather than several separate components.
Good for
- Combines mail, calendars, contacts, and file sharing in one server with one configuration
- Works with standard clients through IMAP, POP3, CalDAV, CardDAV, and WebDAV, as well as JMAP
- Can use existing storage, search, directory, and DNS infrastructure instead of replacing it
Stalwart at a glance
- Website
- stalw.art
- Category
- Development › Self-Hosting
- Type
- Website
- Pricing
- Not confirmed. Check the site
- Platforms
- Web
- Open source
- Not stated
- Language
- English
- Last checked
- Oct 6, 2026 · Online when checked
- Listed
- Oct 5, 2026
Stalwart alternatives
Tools and sites you could use instead, ranked by how closely they match.
Popular in Self-Hosting
Well-known listings from the same topic.
Proxmoxproxmox.comCosmoscosmos-cloud.ioopenmediavaultopenmediavault.orgMail-in-a-Boxmailinabox.emailZincSearchzincsearch-docs.zinc.dev1Panel1panel.pro
Stalwart FAQ
Can existing email and calendar clients be used with Stalwart?
The homepage says Stalwart supports JMAP, IMAP, POP3, SMTP, CalDAV, CardDAV, and WebDAV, so clients that use these standard protocols can connect. JMAP is listed as the modern option for new apps.
Can mailboxes be encrypted so the server operator cannot read them?
The homepage states that mailboxes at rest can be encrypted with the user's own S/MIME certificate or OpenPGP key, and says this would keep them unreadable to an operator with disk access. The source presents this as an option, not as a default.
Is something wrong or out of date?
Tell us and an editor will check it.
Own this website?
Claim this listing
Claim the listing and suggest updates yourself. An editor checks every claim first.