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Appian – Low-Code Platform

Kristijan Zdelarec, Junior Developer

Appian is an intelligent business process management (iBPM) and automation system. Its goal is to help you turn great ideas into powerful business applications that deliver significant value. In this post, we will discuss Appian building blocks and their application in creating a business application.

Process Model

The process model is the most important Appian object which contains the definition of a business process created with Business Process Model Notation (BPMN). Appian translates business workflows to executable processes automatically. A process model allows you to execute business rules, manipulate data, integrate with other systems, schedule and automate processes, task users with work, and connect forms and interfaces. the standard Appian process model is usually made of script tasks, user input tasks (which are forms and interfaces), events and smart services such as document generation services.

Appian process model scheme


Events are used in the process model to determine the start and the end of the process and to define other mid-process events. Some of the possible events are:

  • Start event – denotes the beginning of a process in a process model
  • End event – denotes the end of a process in a process model
  • Timer event – timer events can be used to schedule a process activity or to only continue the flow when certain conditions are met.

Script Tasks

Script tasks are used to perform an automated activity (which does not require a user to complete a form). Both input and output variables can be configured after which they are stored in process variables until the process instance dies. Script tasks can be scheduled and set to repeatedly execute the node. They use expression rules, scripts that perform data manipulation and logic operations.

Expression Rules

An expression rule is a stored expression, Appian object, that can be called from other expressions. Expression rules always return a value that may be influenced by one or more inputs and they differ in that their return value is dictated by an expression. Each time the expression is modified and saved, a new version is created, and the rule can be reverted to any of the previous versions at any time. We use expressions to retrieve data from the database, to call integrations and parse their response, and to map and manipulate data.

Appian Expression-rules


Interface objects represent a UI form that is used for user interaction with the application. Interfaces can be designed visually, by dragging and dropping components in visual designer or programmatically, by generating components via expressions. Interfaces use SAIL (Self-Assembling Interface Layer) technology that takes declarative UI definitions to generate dynamic, interactive and multi-platform user experience. On the left side of the interface designer, we can find all UI components which can be dragged and dropped on the canvas in the middle of the designer. On the right side of the designer, we can find definition input variables and their values as well as values of local variables. Furthermore, on the right side we can find properties of the selected UI element on the canvas. 

Appian Interface

Appian Smart Services

Smart services provide specialized business services. The two categories of smart services are Appian Smart Services and Integration Services. Smart services are by default unattended, meaning the activity will execute once activated. However, certain smart services can be configured as attended. Many of the attended smart services also have an associated smart service function available, which can be used in an Appian expression to invoke that smart service independently of a process model.

Appian provides a service for low-code rapid development and process automation which are key factors for every digital business transformation. By combining all the Appian building blocks, we can produce a simple business application that can follow all business flows and rules with low development time and easy maintenance.

As Appian and Camunda BPM Partner we are combining the power of BPM, speed of low code, and our industry knowledge to achieve operational excellence. Our certified developers are using these powerful platforms to connect all processes and functions within the organization. So feel free to reach us

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