AppExpert applications

Last published : Sep 22, 2026
Warning
The application template functionality is deprecated. As an alternative, you can use StyleBooks. For more information, see StyleBooks and Web application firewall StyleBook.
An AppExpert application is a collection of configuration that you set up on the NetScaler appliance. Managing AppExpert applications is simplified by a GUI (GUI) that allows you to specify application traffic subsets and a distinct set of security and optimization policies for processing each traffic subset. Also, it consolidates deployment steps in one view, so you can quickly configure target IP addresses for clients and specify host servers.
After the AppExpert application is set up, you must verify that the application is working correctly. If necessary, you can customize the configuration to suit your requirements.
Periodically, you can verify and monitor the configuration by viewing the counters for various application components, statistics, and the Application Visualizer. You can also configure authentication, authorization, and auditing (authentication, authorization, and auditing) policies for the application.

AppExpert application terminology

Following are the terms used in the AppExpert applications feature and the descriptions of the entities for which the terms are used:
Public endpoint. The IP address and port combination at which the NetScaler appliance receives client requests for the associated web application. A public endpoint can be configured to receive either HTTP or secure HTTP (HTTPS) traffic. All client requests for the web application must be sent to a public endpoint. An AppExpert application can be assigned multiple endpoints.
Application unit. An AppExpert application entity that processes a subset of web application traffic and load balances a set of services that host the associated content. The subset of traffic that an application unit must manage is defined by a rule. Each application unit also defines its own set of traffic optimization and security policies for the requests and responses that it manages. The NetScaler services associated with these policies are Compression, Caching, Rewrite, Responder, and application firewall.
By default, every AppExpert application with at least one application unit includes a default application unit, which cannot be deleted. The default application unit is not associated with a rule for identifying requests and is always placed last in the order of application units. It defines a set of policies for processing any request that does not match the rules that are configured for the other application units. Thereby ensuring all client requests are processed.
Service. The combination of the IP address of the server that hosts the web application instance and the port to which the application is mapped on the server, in the format \<IP address\>:\<Port\>. A web application that serves many requests is hosted on multiple servers. Each server is said to host an instance of the web application, and each such instance of the web application is represented by a service on the NetScaler appliance.
Application unit rule. Advanced policy expression that defines the characteristics of a traffic subset for an application unit. The following example rule is a Advanced policy expression that identifies a traffic subset that consists of four image types:
HTTP.REQ.URL.SUFFIX.EQ("bmp") || HTTP.REQ.URL.SUFFIX.EQ("gif") || HTTP.REQ.URL.SUFFIX.EQ("png") || HTTP.REQ.URL.SUFFIX.EQ("jpg")
For more information about Advanced policy expressions, see Policies and Expressions.
Traffic Subset. A set of client requests that require a common set of traffic optimization and security policies. A traffic subset is managed by an application unit and is defined by a rule.