Overview
In SMS communication, the sender ID defines how a message appears on a recipient’s device and how replies are processed by the system.
Choosing a sender ID is a foundational decision, as it directly affects inbound messaging capabilities, group design, automation options, and operational costs.
Note
Sender ID availability and configuration options depend on the destination country and local mobile operators. In some countries, alphanumeric sender IDs are not supported, while in others short codes or long numbers may be unavailable. Always verify supported sender types and registration requirements for each target country before finalizing your SMS setup.
Before configuring inbound SMS handling, reply behavior, or automations, it is important to understand the supported sender ID types and their limitations.
Sender ID Types in Mapp Engage
Mapp Engage supports different sender ID types depending on country, provider, and use case. Each sender ID type has specific technical implications.
Alphanumeric Sender IDs
An alphanumeric sender ID displays a brand or company name as the sender of an SMS message (for example, TURTLE&ROO).
Characteristics:
Improves brand recognition
Commonly used for outbound-only SMS campaigns
Does not support inbound SMS replies
Cannot be used for keywords, subscriptions, or reply-based automations
May require registration or approval depending on the country
Because inbound replies are not technically possible, alphanumeric sender IDs are suitable for scenarios where no interaction is expected, such as announcements or drive-to-store campaigns.
Numeric Sender IDs (Short Codes and Long Numbers)
Numeric sender IDs use a phone number as the sender of the SMS message.
Characteristics:
Required for inbound SMS communication
Support replies, keywords, and opt-in / opt-out flows
Enable reply handling, subscriptions, and automations
Require provisioning and registration with mobile operators
Involve setup and ongoing maintenance costs
Only numeric sender IDs allow Mapp Engage to associate inbound messages with groups and apply reply handling or automation logic.
Inbound Messaging Requirements
Inbound SMS replies are only possible when a numeric sender ID is used.
This includes:
Reply handling
Keyword-based interactions
SMS subscriptions and unsubscriptions
Event-based automations triggered by inbound messages
If an alphanumeric sender ID is used, inbound SMS messages cannot be received or processed by the system.
Number Provisioning and Costs
Using numeric sender IDs typically involves additional operational requirements:
Setup or registration fees
Country-specific approval processes
Ongoing leasing or maintenance costs
Limited availability depending on region and operator
The exact requirements depend on the target country and SMS provider.
For details on available providers and registration processes, contact your Mapp account manager.
Impact on Group and Inbound Design
The choice of sender ID directly influences how SMS groups must be structured:
Inbound SMS communication requires numeric sender IDs
Each numeric sender ID or keyword typically maps to one or more dedicated groups
Group reply handling must align with the selected sender ID
Changing sender ID types later often requires restructuring groups and automations
For this reason, sender ID selection should be completed before configuring inbound SMS handling or group reply behavior.