Stalwart Mail Server

Secure & Modern All-in-One Mail Server (IMAP, JMAP, SMTP) 🛡️

continuous integration License: AGPL v3 Documentation
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**Stalwart Mail Server** is an open-source mail server solution with JMAP, IMAP4, and SMTP support and a wide range of modern features. It is written in Rust and designed to be secure, fast, robust and scalable. Key features: - **JMAP** server: - JMAP Core ([RFC 8620](https://datatracker.ietf.org/doc/html/rfc8620)) - JMAP Mail ([RFC 8621](https://datatracker.ietf.org/doc/html/rfc8621)) - JMAP for Sieve Scripts ([DRAFT-SIEVE-19](https://www.ietf.org/archive/id/draft-ietf-jmap-sieve-19.html)) - JMAP over WebSocket ([RFC 8887](https://datatracker.ietf.org/doc/html/rfc8887)), JMAP Blob Management ([RFC9404](https://www.rfc-editor.org/rfc/rfc9404.html)) and JMAP for Quotas ([RFC9425](https://www.rfc-editor.org/rfc/rfc9425.html)) extensions. - **IMAP4** server: - IMAP4rev2 ([RFC 9051](https://datatracker.ietf.org/doc/html/rfc9051)) full compliance. - IMAP4rev1 ([RFC 3501](https://datatracker.ietf.org/doc/html/rfc3501)) backwards compatible. - ManageSieve ([RFC 5804](https://datatracker.ietf.org/doc/html/rfc5804)) server. - Numerous [extensions](https://stalw.art/docs/development/rfcs#imap4-and-extensions) supported. - **SMTP** server: - Built-in [DMARC](https://datatracker.ietf.org/doc/html/rfc7489), [DKIM](https://datatracker.ietf.org/doc/html/rfc6376), [SPF](https://datatracker.ietf.org/doc/html/rfc7208) and [ARC](https://datatracker.ietf.org/doc/html/rfc8617) support for message authentication. - Strong transport security through [DANE](https://datatracker.ietf.org/doc/html/rfc6698), [MTA-STS](https://datatracker.ietf.org/doc/html/rfc8461) and [SMTP TLS](https://datatracker.ietf.org/doc/html/rfc8460) reporting. - Inbound throttling and filtering with granular configuration rules, sieve scripting and milter integration. - Distributed virtual queues with delayed delivery, priority delivery, quotas, routing rules and throttling support. - Envelope rewriting and message modification. - **Spam and Phishing** filter: - Comprehensive set of filtering **rules** on par with popular solutions. - Statistical **spam classifier** with automatic training capabilities. - DNS Blocklists (**DNSBLs**) checking of IP addresses, domains, and hashes. - Collaborative digest-based spam filtering with **Pyzor**. - **Phishing** protection against homographic URL attacks, sender spoofing and other techniques. - Trusted **reply** tracking to recognize and prioritize genuine e-mail replies. - Sender **reputation** monitoring by IP address, ASN, domain and email address. - **Greylisting** to temporarily defer unknown senders. - **Spam traps** to set up decoy email addresses that catch and analyze spam. - **Flexible and scalable**: - Pluggable storage backends with **RocksDB**, **FoundationDB**, **PostgreSQL**, **mySQL**, **SQLite**, **S3-Compatible**, **Redis** and **ElasticSearch** support. - Built-in, **LDAP** or **SQL** authentication backend support. - Full-text search available in 17 languages. - Disk quotas. - Sieve scripting language with support for all [registered extensions](https://www.iana.org/assignments/sieve-extensions/sieve-extensions.xhtml). - Email aliases, mailing lists, subaddressing and catch-all addresses support. - Integration with **OpenTelemetry** to enable monitoring, tracing, and performance analysis. - **Secure and robust**: - Encryption at rest with **S/MIME** or **OpenPGP**. - Automatic TLS certificate provisioning with [ACME](https://datatracker.ietf.org/doc/html/rfc8555). - OAuth 2.0 [authorization code](https://www.rfc-editor.org/rfc/rfc8628) and [device authorization](https://www.rfc-editor.org/rfc/rfc8628) flows. - Automated blocking of hosts that cause multiple authentication errors (aka **fail2ban**). - Access Control Lists (ACLs). - Rate limiting. - Security audited (read the [report](https://stalw.art/blog/security-audit)). - Memory safe (thanks to Rust). ## Get Started Install Stalwart Mail Server on your server by following the instructions for your platform: - [Linux / MacOS](https://stalw.art/docs/install/linux) - [Windows](https://stalw.art/docs/install/windows) - [Docker](https://stalw.art/docs/install/docker) All documentation is available at [stalw.art/docs/get-started](https://stalw.art/docs/get-started). ## Support If you are having problems running Stalwart Mail Server, you found a bug or just have a question, do not hesitate to reach us on [Github Discussions](https://github.com/stalwartlabs/mail-server/discussions), [Reddit](https://www.reddit.com/r/stalwartlabs), [Discord](https://discord.gg/aVQr3jF8jd) or [Matrix](https://matrix.to/#/#stalwart:matrix.org). Additionally you may become a sponsor to obtain priority support from Stalwart Labs Ltd. ## Roadmap - [x] Performance enhancements - [x] Distributed SMTP queues - [ ] Web-based admin panel - [ ] JMAP Calendar, Contacts and Tasks support - [ ] CalDAV and CardDAV support See the [open issues](https://github.com/stalwartlabs/mail-server/issues) for a full list of proposed features (and known issues). ## Funding Part of the development of this project was funded through the [NGI0 Entrust Fund](https://nlnet.nl/entrust), a fund established by [NLnet](https://nlnet.nl/) with financial support from the European Commission's [Next Generation Internet](https://ngi.eu/) programme, under the aegis of DG Communications Networks, Content and Technology under grant agreement No 101069594. If you find the project useful you can help by [becoming a sponsor](https://liberapay.com/stalwartlabs). Thank you! ## License Licensed under the terms of the [GNU Affero General Public License](https://www.gnu.org/licenses/agpl-3.0.en.html) as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. See [LICENSE](LICENSE) for more details. You can be released from the requirements of the AGPLv3 license by purchasing a commercial license. Please contact licensing@stalw.art for more details. ## Copyright Copyright (C) 2024, Stalwart Labs Ltd.