SMS to Email trunk#

An SMS to Email trunk forwards incoming SMS messages from your Direct Inward Dialing (DID) numbers directly to a specified email address. Each message is converted and delivered as a standard email. The trunk settings define the recipient email address and the subject and body of each forwarded email.

How SMS delivery to email works#

When someone sends an SMS to one of your DID numbers, DIDWW uses the SMS trunk assigned to that number to determine where to deliver the message. For an SMS to Email trunk, DIDWW converts the message into an email and sends it to the trunk’s Recipient email address.

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flowchart LR

    sender["SMS sender"] --> |sends SMS| did["DID number"]
    did --> |assigned trunk| trunk["SMS to Email trunk"]
    trunk --> |converts SMS to email| mailbox["Recipient mailbox"]

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    class sender,mailbox endpoint
    class did,trunk process

    linkStyle default stroke:#0066cc,stroke-width:1.5px

For the sender address of forwarded emails and how to keep them from being filtered as spam, see SMS to Email delivery in the Inbound SMS guidelines.

Email subject and body#

The Email subject and Email body settings are templates for each forwarded email. Variables in the templates are replaced with the details of the received SMS. For example, {SMS_SRC_ADDR} inserts the sender address, {SMS_DST_ADDR} inserts the DID number that received the message, and {SMS_TEXT} inserts the message text. For all available variables, see Email subject and body variables.

A long SMS that the sender’s network splits into several parts is delivered as one email. The email contains the complete, reassembled message text. Each part is still billed as a separate fragment. For encoding limits, concatenation, and fragment billing, see SMS encoding reference.

When to use an SMS to Email trunk#

Use an SMS to Email trunk when incoming messages should arrive in an email inbox and you do not want to run an HTTP endpoint or an SMPP connection to receive them.

If your application should receive messages directly, use an HTTP IN trunk, which delivers each message as an HTTP request, or an SMPP ESME trunk or SMPP SMSC trunk, which exchange messages over SMPP. To compare all SMS trunk types, including trunks for sending SMS, see SMS trunks.

SMS to Email trunks and DID numbers#

A DID number receives the SMS, while the SMS to Email trunk defines where and how the message is forwarded by email. To receive messages, assign the trunk or an SMS trunk group containing it to one or more DID numbers that support inbound SMS. Multiple DID numbers can use the same trunk. The default email subject includes {SMS_DST_ADDR}, so each email shows which DID number received the message.

SMS to Email trunks and trunk groups#

To enable failover, add the trunk to an existing SMS trunk group and assign the group to your DID numbers. Within the trunk group, the trunk’s Priority determines the order in which trunks are used. The system attempts to contact the target SMS trunk with the highest-numbered priority first.