Contexts are a way of relating a set of URLs together.
You can define any contexts you like, but it is expected that a context will correspond to a web application.
It is recommended that you define a new contexts for each web application that makes up the system you are testing, and set them in scope as you test each one.

Contexts are defined as a set of regular expressions (regexs) which are applied to all of the URLs in the Sites tab.
Note: The regular expressions must match the whole URL.

You can configure contexts via:

See also

UI Overview for an overview of the user interface
Features provided by ZAP
Structural Modifiers controls which change how ZAP represents the structure of the application