Appian Services Low-Code Module

The Appian Services module extends robotic process automation capabilities within your Appian applications. Using the methods within the module, your process can automatically send data to or request data from Appian numerous times throughout the process execution. These actions occur without initiating an Appian process model, making communication faster and simpler.

Additionally, the module is built for ease of use between environments:

  • It automatically references the environment's base URL so there's no need to hard-code it in the robotic process or update it when deploying to Production.
  • Authentication is simpler and more secure by eliminating the need to use environmental variables and credentials. Appian actions are executed in the context of the user who starts the robotic process. In most cases, the robotic process initiator is actually the service account that already authenticates Appian and Appian RPA. The Appian Services module relies on this authentication mechanism when executing robotic processes, eliminating the need for additional credentials to be defined in the Appian RPA Console or referenced in the robotic process code.

To use the methods in this module, you can use the low-code module available in the Appian RPA Console. The low-code module allows you to easily configure methods in a user interface and call robotic process variables to use as values or store returning method results.

This page describes how to use methods in the low-code module. For more experienced developers, more options are available using the Java module.

Using the Appian Services low-code module

Using methods from a low-code module is both easier and more robust. The Appian Services low-code module allows you to configure the Start process method and the Evaluate expression method through a user interface.

Start process

The Start Process method lets you kick off a process in Appian as part of a robotic process. You can map variables from a process model in Appian to the robotic process variables you've defined in the configuration. The method passes data from Appian RPA variables to Appian using this map and initiates a process using the data as input.

To use the Start Process method:

  1. Go to the Appian RPA Console and open the Robotic Processes tab.
  2. Open a robotic process configuration and navigate to the Robotic process variable section.
  3. Create and save robotic process variables that will map to the variables in the process model you want to reference in a workflow action.
  4. On the Robotic process configuration page, navigate to an action in the workflow.
  5. Click the action and click the list icon 951644.png.
  6. From the Module tree, open the Appian Services module and click Start Process.
  7. In the Process Model field, search for the process model to reference. As you type, Appian RPA suggests available process models to choose from.
  8. Select a process model and the process parameters appear.

    If you don't have access to the selected process model, you'll see a message saying it's not visible and you won't be able to load the process parameters.

  9. If your process variables use primitive data types, you can map them to robotic process variables.
  10. You can also save the overall process ID to a variable in the Save Process ID to menu.
  11. Click OK to save.


Once you've mapped your process variables to the variables in your robotic process, you can reference those variables using other low-code modules in your workflow. This allows you to easily capture and use those values throughout your robotic process without going into your source code.

Evaluate expression

The Evaluate expression method allows you to write and evaluate regular expressions and Appian expressions directly in your robotic process. This method provides an expression pane where you can call Appian expression rules (rule!) and constants (cons!), reference robotic process variables (pv!), and use Appian functions to format and aggregate your data.

This action is particularly helpful with conditional actions. With this method, you can create an if statement that can determine which output the robotic process should follow. In a generic action, this method allows you to determine a variable's value using logic, allowing your data to be dynamic.

To use the Evaluate expression method:

  1. Go to the Appian RPA Console and open the Robotic Processes tab.
  2. Open a robotic process configuration and navigate to an action in the workflow.
  3. Click the action and click the list icon 951644.png.
  4. From the Module tree, open the Appian Services module and click Evaluate Expression.
  5. In the Edit Expression pane, enter a regular expression or Appian expression. As you type, the editor will suggestion functions and objects to reference in your expression.
  6. Use the Operator dropdown to store the result or append the result of the expression to a robotic process variable.
  7. In the Save Into field, enter the name of a robotic process variable.
  8. Click OK to save.

evaluate expression

Loop through a list

It's common for a robotic process to iterate over many items. For example, you could process several employees, IDs, or bank accounts. To process numerous items, a robotic process workflow will include a loop.

Loops utilize conditional actions to determine when all available items have been processed, and which action to take next. Using the Evaluate expression method, it's now easier than ever to construct an if statement in your conditional action to determine if there are anymore items to process.

The example below illustrates how to create a low-code loop in your workflow.


  1. In the Robotic process configuration page, create a new process variable to provide the current index of the loop. In the initial value field, enter the first index number. In many cases, this will be 1.


  2. Create a generic action and use the Evaluate expression method from the Appian Services module. Create an expression that will increment the index after each flow in the loop completes. The expression should save the output back into your index variable. In the example workflow above, this action would be Increment Index.

     pv!currentIndex + 1
  3. Create a conditional action and use the Evaluate expression method from the Appian Services module. Enter an expression to compare the current item's index to the length of the list of total items. In this example, we are comparing the current item index with the total number of contracts. There is no need to save the output back into a variable.

       pv!currentIndex <= length(pv!contracts),

When the robotic process reaches this point of the workflow, it will continue looping through the actions as long as the current index is less than the number of contracts. When the index equals or exceeds the number of contracts, the conditional action routes the robotic process to another action or to end the execution.

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