Used in HTTP Collector and HTTP Exporter → URL Expression.
The URL to be used, without the leading http:// prefix. If this field is blank, the URL field on the HTTP Datasource Instance is used directly.
You can embed expressions in the URL by enclosing the expression in ${…}. Syntax rules depend on the response language; see Embedded Expressions.
Example
This expression adds to the base URL provided by the HTTP datasource instance: {_url}/sub1/sub2?param1=3