> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cognite.com/llms.txt
> Use this file to discover all available pages before exploring further.

# About the Cognite OPC UA extractor

> Learn about the Cognite OPC UA extractor that reads time series, events, and asset information via the OPC UA protocol and streams data and events to time series in Cognite Data Fusion (CDF).

The OPC UA extractor supports the following:

* **Security** using a username/password or automatically generated client/server certificates.
* **Mapping a node hierarchy** from an arbitrary root node to CDF.
* **Subscribing to data changes** in OPC UA and pushing these to destinations.
* **Pushing to more than one destination type**, such as CDF and InfluxDB. You can configure only one InfluxDB database per extractor.
* **Reading historical data** from OPC UA, starting from the earliest last point found in all push destinations.
* **Using properties** in OPC UA as metadata in CDF.
* **Numerical data types** in OPC UA. By default, these are basic types, but you can add additional types in the configuration.
* **String values**: Non-array data types in OPC UA can be converted to strings and then pushed to CDF.
* **Variables** in - UA with an array-type data type of fixed length can be mapped to different measurements in influx or time series in CDF.
* **Setting up a list of events** during the configuration. The event properties are automatically mapped and used as metadata in CDF.
* **Using different emitters** for events than the server node.
* **Discovering new nodes** through auditing or by periodically re-browsing the node tree.