description	Introducing Elsa Workflows 3

Elsa Workflows 3

Elsa Workflows is a set of open-source .NET libraries designed to enhance .NET applications with workflow capabilities. Think of it as lego blocks for creating workflow engines in .NET.

{% hint style="info" %} These docs target the Elsa 3.8.0 stable package family. See Upgrade to Elsa 3.8.0 for the release sources, security defaults, and module registration checklist. {% endhint %}

Workflows in Elsa can be defined in different ways:

• Programmatically by writing .NET code.
• Visually using the built-in designer, non-developers or those who prefer a visual approach can create and modify workflows with ease.
• Declaratively using JSON.

Defining Workflows

Define workflows programmatically using .NET code:

// Define workflows directly from code.
var workflow = new Sequence
{
    Activities =
    {
        new WriteLine("Hello World!"),
        new Delay(TimeSpan.FromSeconds(1)),
        new WriteLine("It is nice to meet you!")
    }
};

And/or, define workflows visually using Elsa Studio:

Design workflows visually

And/or, define workflows declaratively using JSON:

{
  "id": "1",
  "definitionId": "1",
  "name": "Hello World",
  "version": 1,
  "root": {
    "id": "Flowchart1",
    "type": "Elsa.Flowchart",
    "activities": [
      {
        "id": "WriteLine1",
        "type": "Elsa.WriteLine",
        "text": {
          "typeName": "String",
          "expression": {
            "type": "Literal",
            "value": "Hello World!"
          }
        }
      }
    ]
  }
}

Use Cases

1. Integrate Workflow Execution in .NET Applications: Add workflow execution capabilities to existing applications.
2. Standalone Workflow Server: Deploy Elsa as an independent workflow server to manage various business processes across your organisation.
3. Prebuilt Docker Containers: Instead of building a custom workflow server, there is the option of hosting a prebuilt Docker image that acts as a standalone workflow server that exposes REST APIs to interact with the engine.

Key Features

1. Long & Short Running Workflows: Workflows can both be short-lived completing in milliseconds, as well as long-lived, potentially spanning hours, days, weeks, months and even years.
2. Activity Library: Elsa offers a rich set of out-of-the-box activities, providing essential building blocks to construct flexible and effective workflows tailored to your business needs.
3. Triggers: Workflows can be initiated automatically based on specific events or conditions, enabling seamless automation and integration with existing processes.
4. Dynamic Expressions: Elsa allows the use of C#, JavaScript, or Liquid expressions for dynamic value evaluation during runtime, enhancing workflow logic. You can customize it as Elsa is highly modular and extensible.
5. Extensibility: Elsa is built to be extensible, making it easy to add custom activities and connect with other systems.
6. Reusable Web-Based Designer: With the web-based drag & drop designer hosted in Elsa Studio, users can visually create workflows, leveraging a modular and extensible framework.
7. Scalable Performance: Elsa is designed for high performance, working across multiple nodes in a cluster for horizontal scaling.

Known Limitations

Elsa is continually evolving, and while it offers powerful capabilities, there are some known limitations and ongoing work:

• Documentation is still a work in progress.
• The editor's Run Workflow action sends an empty execution request. Use a trigger or the API when the workflow requires inputs or must start through a trigger; the editor does not collect those values in that action.
• Flowchart, Sequence, and StateMachine designers are available in the Elsa Studio 3.8.0 release. Sequence and StateMachine use their own editing surfaces and may expose different editing constraints than Flowchart.
• Studio validates required editor fields and reports server-side validation errors while saving or publishing. It does not provide a general-purpose input form for the Run Workflow action.