# Topic Views

A topic view is a dynamic way to take part of the topic tree and map it to a new set of topics.

A topic view can transform the original topics: for example, changing their values, or expanding them into a new topic tree structure.

This enables the server to transform topic data before sending it to clients.

You can create topic views within the management console, or with the client API.

# Source topics and reference topics

A topic view maps one part of the server's topic tree to another. It takes a set of existing topics (the source topics) and creates a set of reference topics.

Topic view

The reference topics can be a simple mirror of the source topics. The topic view can also transform the source topics, for example by changing their values or properties, expanding them into a different topic structure, or throttling the rate of updates. You specify the details of what a topic view using a topic view specification.

The values and structure of the reference topics change dynamically as the source topics change. Each reference topic has the same topic type as its source topic.

Reference topics are read-only. They cannot be updated, nor can they be created or removed directly. Otherwise, they behave just like standard topics.