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Configuration Reference

Table of contents

  1. Logging
  2. Instance
  3. Service ports
  4. Outgoing emails
    1. Alternative out SMTP
    2. DKIM signing
  5. Forwarding
  6. Spam filtering
  7. Mail database

The configuration is managed by a shared Golang library: config. The configuration files are written in YAML and available in the /etc/mailway/conf.d/ folder.

For convenience, you can print the entire config at once using: mailway config.

The configuration is mostly generated automatically.


  • log_level: Sets the log level in all components. Possible values are: DEBUG, INFO and WARN. Default value: INFO.
  • log_frontline_error: Frontline’s NGINX error log location.
  • log_frontline_http_access: Frontline’s NGINX HTTP access log location.
  • log_frontline_http_error: Frontline’s NGINX HTTP error log location.


  • server_id: unique identifier of the server.
  • server_jwt: JWT token that the server uses to secure the communication with the Mailway dashboard.
  • instance_hostname: public name of the Mailway instance.
  • instance_email: email used to generate certificates.

Service ports

  • port_auth: auth HTTP server port.
  • port_forwarding: forwarding SMTP server port.
  • port_maildb: maildb HTTP server port.
  • port_mailout: mailout SMTP server port.

Outgoing emails

Alternative out SMTP

See how to configure the Alternative out SMTP.

  • out_smtp_host: alternative SMTP hostname.
  • out_smtp_username: alternative SMTP username.
  • out_smtp_password: alternative SMTP password.
  • out_smtp_port: alternative SMTP server port (default: 587).

DKIM signing

  • out_dkim_path: path of the DKIM private key, in PEM format.


  • forwarding_loop_detection_count: number of loops allowed (default: 25).
  • forwarding_rate_limiting_count: number of emails allowed per hour (default: 100).

Spam filtering

  • spam_filter: enable the spam filtering. Possible values: true, false.

This requires configuring a spam filter, not yet documented.

Mail database

  • maildb_db_path: Mail database location on disk (default: $CWD/maildb.db)