What is two way SMS messaging for businesses?
Two way SMS messaging allows businesses to send SMS messages and receive replies from customers using the same channel. Instead of treating SMS as a one direction notification tool, two way SMS enables interaction, feedback, and conversation.
By supporting both outbound and inbound SMS, businesses can communicate at scale while giving customers an easy way to respond using a familiar and widely supported channel.
This article explains what two way SMS messaging is, how it works, and how businesses use it for customer communication and engagement.
What is two way SMS?
Two way SMS is a form of SMS messaging where customers can reply directly to messages sent by a business. Messages are sent from a number or short code that supports inbound replies, allowing communication to flow in both directions.
Two way SMS is typically delivered through a messaging platform using APIs. This allows inbound and outbound SMS to be connected to systems such as CRMs, booking tools, customer support platforms, and backend applications.
MT and MO SMS explained
Two way SMS is built on two types of SMS messages: MT and MO.
MT SMS (Mobile Terminated) refers to messages sent from a business application to a customer’s mobile phone. These are outbound messages such as alerts, reminders, confirmations, or offers.
MO SMS (Mobile Originated) refers to messages sent from a customer’s mobile phone back to a business. These are inbound messages such as replies, confirmations, keyword responses, or support requests.
In two way SMS messaging, MT and MO messages work together to create interaction. A business sends an MT SMS, and the customer responds with an MO SMS, allowing the conversation to continue.
How two way SMS differs from one way SMS
Traditional one way SMS focuses only on MT messages, where no reply is expected. Two way SMS adds MO messaging, allowing customers to respond and engage.
With two way SMS, businesses can:
Invite customers to reply using keywords or free text
Process inbound responses automatically
Route messages to systems or agents
Continue conversations on the same number
This turns SMS into a channel for interaction rather than just notification.
How two way SMS works in practice
Two way SMS can be set up using different sender types depending on the business case and market.
Short codes
Short codes are short numeric sender IDs, typically four to six digits long. They are often used for campaigns, promotions, voting, and service interactions where memorability is important.
Short codes can be:
Dedicated to a single business
Shared across multiple businesses using keywords
Short codes are usually country specific and require local setup.
Long numbers
Long numbers look like standard phone numbers and support two way SMS in many markets. They are commonly used for service conversations, support flows, and international communication.
Local long numbers can also be provisioned in different countries to support regional presence.
Keywords and inbound routing
Keywords help route inbound MO SMS to the correct workflow or system. Customers include a specific keyword in their reply to trigger an action.
Common examples include:
YES to confirm
STOP to opt out
SUPPORT to request help
INFO to receive more details
Keywords allow inbound messages to be processed automatically without manual handling.
Automation and inbound SMS handling
Automation allows two way SMS to scale efficiently. When an MO SMS is received, predefined rules determine how the message is handled.
Automated actions may include:
Sending a confirmation or follow up SMS
Delivering a voucher or access code
Updating customer records
Routing messages to support teams
Triggering callbacks or follow ups
Automation keeps response times short while maintaining consistency.
Opt in and compliance in two way SMS
Two way SMS plays an important role in consent management. Customers often opt in by sending an MO SMS such as START or YES.
In many markets, double opt in is required, meaning customers must confirm their consent before receiving ongoing communication. Messaging platforms manage opt in and opt out handling to support regulatory requirements.
Common business use cases for two way SMS
Two way SMS is used across industries to support interaction and response.
Appointment confirmation and changes
Customer feedback and surveys
Promotions and voucher delivery
Support requests and issue reporting
Service updates with reply options
These use cases show how SMS supports interaction without requiring apps or logins.
Two way SMS with APIs
Modern two way SMS messaging is built using APIs. APIs connect inbound and outbound SMS directly to business systems.
With SMS APIs, businesses can:
Send MT SMS triggered by events
Receive and process MO SMS programmatically
Automate workflows based on replies
Integrate SMS with CRM and support tools
Track delivery and response data
API based SMS messaging supports scalability across markets.
Two way SMS with LINK Mobility
LINK Mobility supports two way SMS messaging through enterprise grade platforms and APIs. Businesses can send and receive SMS while integrating messaging into existing systems and workflows.
Two way SMS can be combined with other messaging channels such as email and chat apps, allowing consistent communication across the customer journey.
By centralizing MT and MO SMS, businesses gain better visibility and control over customer communication.
Using two way SMS to support customer communication
Two way SMS allows businesses to move beyond one direction messaging and support interaction using a familiar channel. Customers can reply easily, and businesses can act on those replies in real time.
By combining SMS reach with APIs and automation, two way SMS supports responsive and scalable communication across markets and industries.
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