✅Transactional SMTP Relay: steps to start sending

Everything you need to know to configure a connecting application to send email through your platform using transactional SMTP Relay

• Create a Connection or MTA policy

• Create a Postal Route for your Connection or MTA Policy

• Create a Customer Account or use the default Acme Customer

• Add the Postal Route to the Customer Account

• Add a User Account under the Customer Account

• Log in as the User Account in Incognito mode or a second web browser

You have to log in directly as the User for this next step.

Don't use administrator impersonation mode.

• Find your User API Key by clicking Integrate -> API & SMTP -> SMTP Relay

• Use the API Key as your username and password

• Connect to your ESP platform DNS hostname or IP address on port 587, 2525, or 8025

• Use STARTTLS or TLS for your encryption method, or choose no encryption

All three ports accept both TLS and disabled/no encryption.

TLS is the only supported encryption method - do not select SSL in your application.

Try connecting using your IP address instead of your domain if you run into issues.

Your transactional SMTP messages will be delivered via the Customer's Postal Route.

Mail comes into your Transactional SMTP Relay on port 587, 2525, or 8025 and goes out of the Connection or MTA Policy configured in the Postal Route assigned to your Customer Account in the administrative backend.

All mail delivered from your ESP platform follows the same pathway:

Broadcast, Funnel, or Transactional Message -> Customer Account -> Postal Route -> API Connection, SMTP Relay Connection, or MTA Policy -> Gmail/Yahoo/Outlook/etc

You can actually use whatever you want for the Transactional SMTP Relay username.

We recommend using the API Key for the username and password for simplicity of explanation, but the username is actually ignored and discarded and can be anything.

If you're using Cloudflare for HTTPS, extra steps to enable SMTP Relay are required.