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Usesend ​


Usesend dashboard

What is Usesend ​

Usesend is an open-source alternative to Resend, Sendgrid, Mailgun and Postmark etc.

There are some setup to be made, please refer to the official documentation for more information.

SMTP Configuration ​

Running Usesend with SMTP support requires an additional relay component to handle incoming SMTP requests. This relay service binds to multiple ports supporting both SSL and TLS connections.

Prerequisites ​

Before configuring the SMTP relay, you need to add a certificate dumper to your Traefik proxy configuration to make Coolify's SSL certificates accessible to the relay:

  1. Navigate to Server → Proxy → Configuration
  2. Add the following certificate dumper configuration:
yaml
traefik-certs-dumper:
  image: ghcr.io/kereis/traefik-certs-dumper:latest
  container_name: traefik-certs-dumper
  restart: unless-stopped
  depends_on:
    - traefik
  volumes:
    - /etc/localtime:/etc/localtime:ro
    - /data/coolify/proxy:/traefik:ro
    - /data/coolify/certs:/output

This service extracts Traefik-managed certificates and outputs them to /data/coolify/certs/, making them available for the SMTP relay to use for SSL and TLS connections.

Adding the SMTP Relay Service ​

Add the following service at the end of the compose file (by clicking on "Edit compose file" when adding the service):

INFO

Replace ###USESEND FQDN (e.g. usesend.example.com)### with your unsend domain name in the configuration below.

yaml
  smtp-server:
    container_name: usesend-smtp-server
    image: 'usesend/smtp-proxy:latest'
    volumes:
      - type: bind
        source: /data/coolify/certs/###USESEND FQDN (e.g. usesend.example.com)###/key.pem
        target: /data/certs/key.pem
        read_only: true
      - type: bind
        source: /data/coolify/certs/###USESEND FQDN (e.g. usesend.example.com)###/cert.pem
        target: /data/certs/cert.pem
        read_only: true
    environment:
      - SMTP_AUTH_USERNAME=usesend
      - SERVICE_FQDN_SMTP
      - 'USESEND_BASE_URL=${SERVICE_URL_USESEND_3000}'
      - USESEND_API_KEY_PATH=/data/certs/key.pem
      - USESEND_API_CERT_PATH=/data/certs/cert.pem
    ports:
      - '25:25'
      - '587:587'
      - '2587:2587'
      - '465:465'
      - '2465:2465'
    healthcheck:
      test:
        - CMD
        - nc
        - -z
        - localhost
        - "25"
      interval: 30s
      timeout: 10s
      retries: 3
      start_period: 10s

Then add those environment variables to the main Usesend service:

yaml
      - SMTP_HOST=${SERVICE_FQDN_SMTP}
      - SMTP_USER=${SMTP_AUTH_USERNAME}

Using Usesend SMTP in Your Applications ​

Once the relay is deployed, configure your sending applications with the following settings:

  • SMTP Host: Your Usesend URL
  • SMTP Port: 465 (SSL) or 587 (TLS/STARTTLS)
  • Username: usesend
  • Password: Your Usesend API key (generated from the Usesend dashboard)

The relay supports multiple ports for compatibility with different applications:

  • Standard SMTP: Ports 25, 587, 2587
  • SSL/TLS: Ports 465, 2465

You can verify that emails are being sent successfully through Usesend's deliverability reports and message previews in the dashboard.