Modern IT infrastructures are becoming increasingly complex. Organizations rely not only on traditional network devices such as routers, switches, and servers, but also on cloud platforms, custom applications, APIs, and IoT devices. While many monitoring tools provide built-in templates for common systems, they often lack the flexibility required to monitor proprietary or specialized services.

PRTG Network Monitor addresses this challenge through its custom sensor capability. Custom sensors allow administrators to extend monitoring beyond predefined checks and integrate virtually any system, service, or application into the monitoring environment.

By leveraging scripts, APIs, and external data sources, PRTG enables IT teams to build highly flexible monitoring solutions tailored to their infrastructure.

What Are Custom Sensors in PRTG?

A custom sensor in PRTG is a user-defined monitoring component designed to collect data that standard sensors cannot access. These sensors allow administrators to retrieve metrics from external scripts, custom endpoints, or proprietary systems.

Custom sensors typically collect information using:

• PowerShell scripts

• Python scripts

• Executable applications

• REST APIs

• HTTP endpoints returning JSON or XML

• Custom SNMP OIDs

This flexibility allows PRTG to monitor virtually anything that can return structured data.

Types of Custom Sensors

PRTG supports several sensor types that can be used for custom monitoring scenarios.

EXE/Script Advanced Sensor

The EXE/Script Advanced sensor allows administrators to execute external scripts or programs and return monitoring data to PRTG.

Supported scripting languages include:

• PowerShell

• Python

• Batch scripts

• VBScript

• Executable binaries

The script returns output in XML or JSON format, which PRTG interprets as monitoring channels.

Example use cases include:

• Monitoring custom applications

• Retrieving database metrics

• Parsing log files

• Tracking internal service performance

HTTP Advanced Sensor

The HTTP Advanced sensor retrieves data via HTTP requests or REST APIs.

This sensor type is particularly useful for monitoring:

• Cloud platforms

• SaaS applications

• Web services

• IoT devices

The response from an API endpoint can be parsed and converted into sensor channels for visualization and alerting.

SNMP Custom Sensor

Many hardware vendors expose additional metrics using custom SNMP OIDs that are not included in standard monitoring templates.

Custom SNMP sensors allow administrators to monitor:

• Hardware health metrics

• Temperature sensors

• Fan speeds

• Power consumption

This enables deeper monitoring of specialized hardware environments.

REST API Monitoring

Many modern applications provide metrics through REST APIs.

Using custom sensors, PRTG can monitor:

• Kubernetes cluster metrics

• Application health endpoints

• Cloud service status

• Microservice performance metrics

This capability allows PRTG to integrate seamlessly with modern DevOps ecosystems.

Practical Use Cases

Monitoring Custom Applications

Organizations frequently develop internal applications that require monitoring beyond standard infrastructure metrics.

Custom sensors can track:

• API response times

• Queue lengths

• Application error rates

• Service availability

Monitoring IoT and Industrial Systems

Industrial and IoT environments often rely on specialized hardware and protocols.

Custom sensors allow organizations to monitor:

• Industrial production machines

• Environmental sensors

• PLC devices

• Energy usage systems

Monitoring Cloud Platforms

As organizations adopt hybrid and multi-cloud infrastructures, custom sensors enable monitoring of services such as:

• AWS APIs

• Microsoft Azure services

• Google Cloud metrics

• Third-party SaaS platforms

Creating a Custom Sensor in PRTG

The process of creating a custom sensor typically involves three main steps.

Step 1: Create a Script

Administrators write a script that retrieves the desired metric and returns the result in XML or JSON format.

Example PowerShell output structure:

<prtg>
  <result>
    <channel>CPU Usage</channel>
    <value>45</value>
  </result>
</prtg>

Step 2: Store the Script in the Custom Sensor Directory

The script should be placed in the appropriate PRTG directory on the probe system.

PRTG\Custom Sensors\EXEXML

Step 3: Add the Sensor in the PRTG Interface

Within the PRTG web interface:

1. Select the device

2. Click Add Sensor

3. Choose EXE/Script Advanced

4. Select the script and configure parameters

Once added, the sensor will begin polling the script at the defined interval.

Best Practices for Custom Sensors

To ensure stable and efficient monitoring, consider the following best practices:

• Keep scripts lightweight and efficient

• Avoid unnecessary API calls

• Use appropriate polling intervals

• Implement error handling within scripts

• Validate JSON or XML output formatting

Careful design ensures that custom sensors scale effectively even in large environments.

Advantages of Custom Sensors

Custom sensors significantly extend the capabilities of PRTG by enabling:

• Monitoring of proprietary systems

• Integration with APIs and cloud services

• Visibility into internal applications

• Monitoring of IoT and industrial environments

By leveraging custom sensors, organizations can transform PRTG from a traditional network monitoring tool into a comprehensive infrastructure monitoring platform.

Conclusion

PRTG's flexible sensor architecture allows organizations to monitor far more than standard network devices. Custom sensors enable IT teams to integrate custom applications, APIs, and specialized infrastructure into a centralized monitoring platform.

With properly implemented custom sensors, organizations gain greater visibility into their infrastructure, detect problems earlier, and improve operational efficiency.

For modern IT environments that require adaptability and scalability, custom sensors are an essential feature of PRTG Network Monitor.