What type of parameters must be saved to process variables in Appian?

In Appian, parameters that need to be saved to process variables are specifically related to the context of the process model and its execution. Activity Class Parameters are designed to hold runtime data that can change during the execution of a process. These parameters are typically defined in the activity class of a process and can be utilized across different nodes of the process, making them essential for maintaining state and sharing information.

When you save Activity Class Parameters to process variables, you ensure that the data is retained and accessible throughout the lifespan of the process instance. Their ability to hold values that may need to be referenced later in the process contributes to dynamic process management and enhances versatility in application logic.

Other types of parameters, such as Task Parameters, Expression Parameters, and Custom Parameters, serve different purposes within Appian and are not primarily designed to be saved to process variables in the same direct manner as Activity Class Parameters. Task Parameters relate to the specific settings of a user task, Expression Parameters are used within expressions for data manipulation without the direct context of a process variable, and Custom Parameters might refer to user-defined values that do not inherently link to the structural process flow. Thus, Activity Class Parameters stand out as the correct choice for saving to process variables in Appian.