Elsa Workflows — Visual Workflow Engine for .NET

Introduction

Elsa is a workflow engine for .NET that supports building long-running, stateful workflows. Developers can define workflows in C# code, JSON, or through a built-in visual designer. It handles orchestration of HTTP endpoints, timers, events, and custom activities.

What Elsa Does

• Executes long-running workflows with persistence and resumption across restarts
• Provides a visual drag-and-drop workflow designer accessible via web browser
• Supports code-first workflow definitions using a fluent C# API
• Offers built-in activities for HTTP requests, timers, email, and JavaScript evaluation
• Triggers workflows from HTTP endpoints, message queues, cron schedules, or custom events

Architecture Overview

Elsa separates workflow definitions from runtime execution. Definitions are stored as JSON or compiled from C# code, and the runtime engine manages instances, bookmarks, and resumption points. A persistence layer supports EF Core, MongoDB, or custom providers. The workflow designer is a Blazor-based SPA that communicates with the engine via REST APIs.

Self-Hosting & Configuration

• Install via NuGet: dotnet add package Elsa plus activity packages like Elsa.Http or Elsa.Email
• Register Elsa services in Program.cs with builder.Services.AddElsa()
• Configure persistence with SQLite, SQL Server, PostgreSQL, or MongoDB
• Mount the workflow designer UI with app.UseElsaStudio() for visual editing
• Deploy as a standard ASP.NET Core application behind any reverse proxy

Key Features

• Visual designer for non-developers to create and modify workflows
• Code-first and designer-first workflows can coexist in the same application
• Versioned workflow definitions with rollback support
• Built-in activity library covering HTTP, scripting, branching, and looping
• Extensible with custom activities written in C#

Comparison with Similar Tools

• Temporal — Language-agnostic durable execution; Elsa is .NET-native with a visual designer
• n8n — Node.js workflow automation; Elsa integrates directly into .NET applications
• Camunda — Java-based BPMN engine; Elsa is lighter weight and C#-native
• Conductor (Netflix) — Microservice orchestrator; Elsa targets .NET monoliths and modular apps

FAQ

Q: Can workflows survive application restarts? A: Yes, Elsa persists workflow state and bookmarks to a database and resumes automatically.

Q: Is the visual designer included? A: Yes, the Elsa Studio designer is included as a NuGet package and runs as a Blazor WebAssembly app.

Q: Can I run Elsa without the designer? A: Yes, you can define workflows entirely in C# code and run them headlessly.

Q: What .NET versions are supported? A: Elsa 3.x targets .NET 8 and later.

Sources

• https://github.com/elsa-workflows/elsa-core
• https://v3.elsaworkflows.io