An industrial extract, transform, and load (ETL) system extracts and transfers data from proprietary industrial systems and devices to cloud-level systems or other higher level applications. The industrial ETL system uses application connectors that are designed to interface with various types commonly used or proprietary industrial systems and devices—including but not limited to industrial controllers, open platform communications (OPC) servers, databases, MQ telemetry transport (MQTT) brokers, motor drives, telemetry devices, etc.—and to extract data from those systems in a manner that reduces the impact on those systems' core functionalities relative to conventional ETL approaches. The system's application connectors use the same technology stack to communicate with multiple different devices and systems that are commonly found in industrial software architectures.