FeatherMail

Welcome to Feather Mail

Feather Mail is a modern, developer-friendly email server framework. Whether you're building a personal mail server, a SaaS product, or integrating email into a larger system, Feather Mail gives you full control over your email pipelines — without forcing you to navigate decades of legacy mail server complexity, shout out to sendmail.

Built on top of Elixir and the rock-solid BEAM runtime, Feather Mail combines fault-tolerance, concurrency, and scalability with a clean, pluggable interface designed for developers.

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Installation

From a release tarball

Download the latest release for your platform from Releases, then:

tar -xzf feather-linux-amd64.tar.gz
cd feather
sudo ./install.sh

This creates a feather system user, installs the release to /opt/feather (Linux) or /usr/local/feather (FreeBSD), sets up the service file, and copies example config if none exists.

Then enable and start:

# Linux (systemd)
sudo systemctl enable feather
sudo systemctl start feather

# FreeBSD (rc.d)
sudo sysrc feather_enable=YES
sudo service feather start

To uninstall (config and logs are preserved):

sudo ./install.sh remove

From source

make release
cd _build/prod/rel/feather
sudo ./install.sh

Configuration

After install, edit the config files in /etc/feather (Linux) or /usr/local/etc/feather (FreeBSD):

• server.exs — server settings (bind address, port, TLS)
• pipeline.exs — adapter pipeline (auth, routing, delivery, rate limiting)

Override the config directory with the FEATHER_CONFIG_FOLDER env var.

Managing the service

# systemd
sudo systemctl start|stop|restart|status feather
journalctl -u feather -f

# FreeBSD
sudo service feather start|stop|status

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Why Feather Mail?

Traditional mail servers can be intimidating:

• Complex configuration formats
• Rigid role separation
• Difficult to extend
• Opaque error handling

Feather Mail offers a different approach:

• Unified pipeline model: All email flows through a pipeline you define.
• Role-agnostic design: There is no hardcoded distinction between MSA, MTA, or MDA — your configured pipeline defines the role.
• Pluggable architecture: Easily extend Feather Mail with Adapters and Transformers.
• Transparent processing: You see exactly what happens at every stage.
• Built for customization: Authentication, filtering, aliasing, forwarding, delivery — all under your control.

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Who is Feather Mail for?

• Developers building platforms needing custom mail flows.
• System administrators who want more visibility and control.
• Builders of private or organizational mail servers.
• Anyone frustrated by traditional, existing options and looking for a modern alternative.

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What Feather Mail is NOT

• It's not a drop-in Postfix/Exim replacement (yet, we will surely get there).
• It's not an IMAP server (though it integrates well with IMAP backends like Dovecot).
• It's not a black-box appliance — Feather Mail prioritizes transparency and control.

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Core Concepts (Preview)

Feather Mail is built around a few simple but powerful ideas:

• Pipelines: Every mail transaction flows through a configurable pipeline of stages.
• Adapters: Each adapter attaches logic for access control, routing, delivery, forwarding, and more.
• Transformers: Small, composable units to modify message metadata during processing.
• Role-agnostic: You define the behavior — Feather Mail doesn’t enforce artificial distinctions between submission, transfer, or delivery.