SMPP (Short Message Peer-to-Peer) is a protocol used by the telecommunications industry for exchanging SMS messages between Short Message Service Centers (SMSC) and External Short Messaging Entities (ESME). The SMPP protocol is sent through TCP/IP, which allows faster delivery of SMS messages.

The most commonly used versions of SMPP are v3.3, the most widely supported standard, and v3.4, which adds transceiver support (single connections that can send and receive messages).

SMPP Latest Version

The kaleyra Messaging Platform uses the SMPP v3.4 Protocol Specification Issue 1.2.

This document should be read in conjunction with SMPP v3.4 Specifications v1.2 and assumes with SMPP a level of familiarity and functionality.

Connecting to the SMPP Service

Clients may connect to the Kaleyra Messaging Platform Server multiple numbers of times. This may be of importance if the client wishes to deploy multiple applications simultaneously. To connect to the Kaleyra Messaging Platform, one needs to specify the following parameters:




Supplied separately


Supplied separately


SMPP V3.3 OR V 3.4


Transmitter (TX)/ Receiver (RX)/ Transceiver (TRX)


Supplied separately


Supplied separately

IP Address and Port
This is the TCP/IP endpoint on which the ESME should connect to the Kaleyra Messaging Platform.

This is the username of your account configured on the Kaleyra Messaging Platform

Password for the above account. Required for security reasons to prevent unauthorized access to your account.

Set the system_type field to smpp.

The client application should connect with the interface_version field set to 0x34 (52 decimal), if it is using SMPP v3.4, otherwise the Kaleyra Messaging Platform assumes that the application uses SMPP v3.3.

  • If the application uses SMPP v3.3, then the optional fields cannot be used. These optional fieldsmay be required to implement extra facilities like lengthy SMS


The application should issue an enquire_link every 60 seconds. This will ensure
the link stays active even when it is not in use. The Kaleyra Messaging Platform will
automatically disconnect any link which is inactive for more than 5 minutes.