Sovite

A modern, secure Mail Transfer Agent written in Elixir/OTP, meant as an alternative to Postfix.

Status: early development. Sovite receives mail over SMTP, queues it durably, and relays it to other servers with retries and bounces (Phases 1–2). It speaks TLS both ways (STARTTLS, implicit TLS, SNI, ACME, DANE) and accepts mail from authenticated clients on submission ports (Phase 3). It routes mail by its own database: hosted domains, aliases, mailboxes, transports, address rewriting, BCC, and access rules at every SMTP stage, all managed with sovitectl (Phase 4). It hands mail to mailbox servers such as Dovecot over LMTP, delivers to Maildir folders and pipe commands, detects mail loops, and can itself listen for LMTP (Phase 5). Email authentication (SPF, DKIM, DMARC) is next. See the roadmap.

Sovite is also a library: its components (address validators, DNS and MX resolution, an SMTP server and client, TLS with DANE and ACME, SASL, LDAP, RFC 5322 address lists, delivery status notifications, and later DKIM, SPF, ...) can be used from any Elixir project without running the MTA. See STRUCTURE.md.

Development

Requires Erlang/OTP 29 and Elixir 1.20 (see mise.toml).

mix setup           # deps.get, and enables the git pre-commit hook
mix test            # tests, including property tests
mix lint            # format check, warnings as errors, credo, xref cycles
mix dialyzer

The pre-commit hook (.githooks/pre-commit) runs mix lint and mix dialyzer and refuses the commit if either fails. The first Dialyzer run builds its PLT and takes a few minutes; later runs are incremental.

Manage routing data (stored in Sovite's database):

sovitectl domain add example.com hosted
sovitectl mailbox add alice@example.com
sovitectl alias add sales@example.com alice@example.com bob@example.com
sovitectl transport set example.com lmtp:unix:/run/dovecot/lmtp
sovitectl access set client 192.0.2 REJECT spam source   # used by client_access in [restrictions]

Run the MTA locally:

cp rel/overlays/etc/sovite.toml.example sovite.toml   # edit as needed
SOVITE_START_MTA=1 SOVITE_CONFIG=./sovite.toml iex -S mix

Build a release:

MIX_ENV=prod mix release
_build/prod/rel/sovite/bin/sovitectl config check _build/prod/rel/sovite/etc/sovite.toml.example
SOVITE_CONFIG=/etc/sovite/sovite.toml _build/prod/rel/sovite/bin/sovite start

Documentation

• Configuration
• Logging and telemetry
• Security model and vulnerability reporting

License

AGPL-3.0. See LICENSE.