Getting Started Sending Email

Remember CloudMailin Outbound is only for Transactional email More information can be found in the outbound email introduction.

This will mainly consist of:

  1. Creating DNS records
  2. Setting your SMTP server access credentials
  3. Monitoring Bounces (highly recommended)
  4. Setting Queue Priorities (optional)
  5. Setting message tags (optional)

DNS Records

We currently require DNS records for SPF, DKIM and to handle bounces. This can all be set using two records.

Normally we will ask to send on a subdomain of your primary domain. For example if your domain is then we will send from

The SMTP conversation will send the message from whilst the message headers remain as

We need to set the following DNS records (these are just examples):

Record Example Description
CNAME A CNAME used to set MX servers for bounces and SPF
TXT The DKIM record placed on the root domain.

Details for your domain specifically cen be found on the domain's detail page.

SMTP Settings

SMTP settings will be available from within the dashboard of your account.

Before you can send email we require SMTP Autentication. You'll need to provide a username and password via LOGIN or PLAIN auth. In order for this to be secure we only accept SMTP Auth once an encrptyed session has been established via the STARTTLS command.

The SMTP transaction will reply with the message-id of the message to use for bounce tracking if required.

250 Thanks! Queued as: f78b876d-dd97-4e10-9a61-067f98044cc7

Monitoring Bounces

Our system will track bounces and non-delivery-reports from mail servers. These events will be sent to you via Webhook. The payload will be a JSON HTTP request with the following format:

  "events": [
      "kind": "bounce",
      "recipient": "",
      "message_id": "f78b876d-dd97-4e10-9a61-067f98044cc7",
      "details": {}

Please note: The list of events is an array. In multiple events may be sent in one HTTP POST.

The list of fields currently POSTed for each entry is as follows:

Field Description
kind The type of event raised. This is one of delivery, bounce, soft_bounce, open, click, complaint, blocked.
recipient The recipient of the message.
message_id The message ID as returned by the SMTP transaction.
details Additional details if present related to the event.

These fields will be expended with additional details over time.