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Using Mailer To Go on Heroku, Addons.io & Build.io

Getting Started

Mailer To Go provides SMTP and API access for transactional email. Whether you deploy on Heroku directly, through Addons.io, or on Build.io, the setup is the same: provision the addon, grab your credentials, and start sending.

Heroku Marketplace

Heroku has been our home since day one, and we are committed to supporting the platform regardless of any changes to the marketplace landscape.

Add Mailer To Go to your app:

heroku addons:create mailertogo --app your-app

This provisions a Mailer To Go account and sets the MAILERTOGO_SMTP_HOST, MAILERTOGO_SMTP_USER, MAILERTOGO_SMTP_PASSWORD, and MAILERTOGO_API_KEY environment variables on your app automatically.

Addons.io

Addons.io is a marketplace for Heroku-compatible addons. Find Mailer To Go in the catalog, click Install, and select the plan that fits your volume. The provisioning flow is identical to Heroku — same environment variables, same API, same dashboard.

Build.io

Build.io is a Heroku-compatible platform that runs your Procfile and app.json natively. Mailer To Go is available as a first-class addon. Add it through the Build.io dashboard or via the CLI:

bld addons:create mailertogo --app your-app

Your app.json can declare the dependency:

{
  "addons": ["mailertogo"]
}

Configuration

Once provisioned, configure your app to use the SMTP credentials:

# config/environments/production.rb
config.action_mailer.smtp_settings = {
  address:        ENV["MAILERTOGO_SMTP_HOST"],
  port:           587,
  user_name:      ENV["MAILERTOGO_SMTP_USER"],
  password:       ENV["MAILERTOGO_SMTP_PASSWORD"],
  authentication: :plain,
  enable_starttls_auto: true
}

Or use the API directly with your MAILERTOGO_API_KEY for programmatic sending, template management, and delivery tracking.

Custom Domains

For production use, configure a custom sending domain in the Mailer To Go dashboard. Add the DNS records we provide (SPF, DKIM, DMARC) to authenticate your domain and maximize deliverability.

Our Commitment

Mailer To Go was built for the Heroku ecosystem. As the platform evolves, we remain available wherever Heroku-compatible apps run — on Heroku itself, on Addons.io, and on Build.io. Your email infrastructure stays stable regardless of where you deploy.