A message's Reference can be used for tracking across the product suite, from Email notifications, to API Webhooks, to Monthly Billing Reports.

When sending Email-to-SMS, Email-to-Fax, Email-to-Voice and Email-to-IM messages, the Reference is the email's Subject.
When sending using the Web Dashboard, the Reference is set when loading a new message.
When using the API, there is a Reference parameter that can be set.

For specific information on how you can track the Reference in your particular configuration, you can contact Support by clicking the link below.

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