# Create Custom Script for MQTT

To create a custom script for MQTT Message Queue Telemetry Transport (MQTT) is a lightweight messaging protocol used to send and receive data between devices. communication, you can either use the default script as a template, or construct the necessary parts of the script using the provided code snippets.

When testing your custom script, use the following diagnostic tools:

- Built-in log viewer: https://{deviceIp}/utilities/single/enterprise-connectivity/diagnostics

- SSE endpoint for logs: https://{deviceIp}/api/edge-agent/diagnostics/user-log

The following subsections of this document provide references and instructions for creating your own custom script.