Communication options

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SMS supports one-way and two-way communication with your customers. Understanding these patterns helps you choose the correct sender type, routing, and message delivery mode.

Infobip supports several common SMS use cases that differ by purpose and communication direction.

Message purpose	Communication direction	Typical sender	Common uses	Requires opt-in
One-way promotional	Outbound only	Alphanumeric	Marketing campaigns	Yes
One-way transactional	Outbound only	Numeric or alphanumeric	OTPs, alerts	No (triggered by action)
Two-way promotional	Outbound and inbound	Long number or short code	Surveys, feedback	Yes
Two-way transactional	Outbound and inbound	Long number or short code	Verifications, confirmations	Usually yes

For OTP and PIN verification scenarios, see 2FA service which provides built-in verification logic and message templates.

NOTE

Some countries require you to register the sender regardless of whether you send one-way or two-way traffic. For regulatory and country-specific requirements, see SMS coverage and connectivity.

One-way SMS [#one-way-sms]

One-way SMS includes outbound messages that do not support replies. These messages are informational or promotional.

Examples	Key characteristics
Delivery notifications and service alerts	Uses alphanumeric or numeric sender IDs
Appointment reminders	Does not support inbound replies
Marketing campaigns and special offers	Suitable for high-volume outbound traffic

Two-way SMS [#two-way-sms]

Two-way SMS supports interactions between your business and users. Recipients can reply, and their replies are processed through Infobip inbound routing.

Examples	Key characteristics
Customer support and feedback requests	Requires a dedicated long number, short code, or verified toll-free number
OTP verification and user confirmations	Supports inbound and outbound traffic
Subscription and preference management (opt-in/opt-out)	Enables automation through keywords and API integrations

Inbound SMS [#inbound-sms]

Inbound SMS enables users to send messages to your business through a long number, short code, or verified toll-free number. These messages are received by Infobip and forwarded to your system using one of several delivery methods. You can use inbound SMS to support two-way conversations, automate actions, or integrate user messages into your existing systems.

Inbound message delivery methods [#inbound-message-delivery-methods-inbound-sms]

Infobip receives mobile originated (MO) messages sent to your number and delivers them to your system using one of the supported methods:

Webhook (HTTP forwarding): Infobip sends each inbound message to your HTTPS endpoint in real time.
API pull: Your system retrieves inbound messages from Infobip by calling the API.
SMPP forwarding: Messages are delivered to your Short Message Service Center (SMSC) over an SMPP bind.
Email forwarding: Messages are forwarded to a designated email address.

These methods support different integration needs. Webhook delivery provides real-time processing, whereas API pull is useful for systems that cannot expose a public endpoint. SMPP suits high-throughput environments or existing SMSCs, and email forwarding supports lightweight workflows.

Configure inbound routing [#configure-inbound-routing-inbound-sms]

Use inbound routing to define how Infobip delivers mobile originated (MO) messages from users to your system.

Before you begin:

You must have a long number, short code, or verified toll-free number that supports inbound SMS.
Your account must have SMS enabled.
You must have permission to access Channels and Numbers.
If you plan to use a webhook, prepare a publicly accessible HTTPS endpoint.

Using the web interface:

Go to Channels and Numbers > SMS.
Select the number you want to configure.
Open the Inbound configuration section.
Choose the delivery method:
- Forward to URL for webhook
- Forward to email for email delivery
- SMPP forward for SMSC integration
- Default inbound if you use API pull
Enter the destination details, such as webhook URL or SMPP connection parameters.
Add optional callback data to help identify messages or sessions.
Select Save.

Verify inbound routing:

Send a test SMS from a mobile device to your number.
Check your system to confirm that the inbound message is received through the selected method.

Inbound message APIs and callbacks [#inbound-message-apis-inbound-sms]

You can define inbound message destinations programmatically using the Infobip inbound SMS API, or receive callbacks from Infobip through a webhook.

Method	Type	Description
Get inbound SMS messages	API (pull)	Retrieves messages sent by end users to your Infobip number. Use this when you want to pull inbound messages (MO) from Infobip instead of receiving them via webhook. Useful for systems that cannot expose a public endpoint.
Receive inbound SMS messages	Webhook (push)	Infobip sends each inbound SMS to your configured HTTPS endpoint in real time. Your endpoint receives a POST request with the payload schema documented in the link above. For webhook retry behavior and security options, see the webhook documentation (placeholder).

Transactional and promotional SMS [#transactional-and-promotional-sms]

Infobip distinguishes between transactional and promotional SMS traffic. The message type affects delivery priority, compliance requirements, and allowed sending times in some regions.

Transactional SMS [#transactional-sms-transactional-and-promotional-sms]

Transactional SMS delivers time-sensitive or service-related information to users.

Examples	Key characteristics
One-time passwords (OTPs)	High delivery priority
Payment confirmations	Must be triggered by user activity or a system event
Account updates or system alerts	Usually requires pre-registered sender IDs in regulated markets

Promotional SMS [#promotional-sms-transactional-and-promotional-sms]

Promotional SMS is used for marketing, campaigns, and offers intended to promote a product or service.

Examples	Key characteristics
Seasonal promotions and discounts	Lower delivery priority
Loyalty program updates	Requires explicit user opt-in
Event invitations	May be subject to sending time restrictions by country

Related pages

Send and track
Submission options, Flash SMS, scheduling, and tracking.

SMS compliance
Review regulations and best practices for your region.

Multilingual SMS
Character encoding, NLI, and transliteration.