FlowForge

Design, execute, and export workflows visually -- a drag-and-drop pipeline builder for .NET.

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Demo

git clone https://github.com/mcandiri/FlowForge.git
cd FlowForge
dotnet run --project src/FlowForge.Web

Open http://localhost:5000 in your browser.

Drag nodes onto the canvas, wire them together, hit Run, and watch the execution trace light up in real time.

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Features

• Visual Designer -- Drag-and-drop canvas with snap-to-grid, auto-layout, and live connection drawing.
• 10+ Node Types -- HTTP requests, conditions, loops, delays, code blocks, email, database queries, and more.
• Real-Time Execution -- Execute workflows directly in the browser and watch each node highlight as it runs.
• C# Code Export -- Generate clean, copy-pasteable C# code from any workflow.
• JSON Import / Export -- Save, share, and version-control your workflows as JSON files.
• Demo Templates -- Five ready-made templates to explore patterns like data pipelines, notifications, loops, error handling, and approval flows.

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Node Types

Icon	Node	Category	Description
🔔	Webhook Trigger	Trigger	Entry point -- starts a workflow from an HTTP webhook
🌐	HTTP Request	Action	GET / POST / PUT / DELETE with mock-mode support
📝	Logger	Action	Log messages with variable interpolation
📧	Email Sender	Action	Send email notifications (demo mode logs instead)
💻	Code Block	Action	Execute arbitrary C# expressions at runtime
📦	Set Variable	Action	Store a value in the workflow context
🗄️	Database Query	Action	Run SQL queries (mock result sets in demo mode)
🔀	Condition	Control	If / else branching on expressions
⏰	Delay	Control	Pause execution for N milliseconds
🔁	Loop	Control	Iterate over a collection variable
🔄	Retry	Control	Retry a failed step up to N times
🔃	Transform	Data	Map and reshape data with variable templates

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Architecture

FlowForge.sln
  src/
    FlowForge.Core/          Core engine, nodes, models, export, templates
      Engine/                 WorkflowEngine, ExecutionContext, NodeExecutor
      Models/                 Workflow, FlowNode, FlowEdge, NodeConfig, NodePort
      Nodes/                  IFlowNode interface + all built-in node implementations
        Actions/              HttpRequest, Logger, EmailSender, CodeBlock, SetVariable, DatabaseQuery
        Control/              Condition, Delay, Loop, Retry
        Data/                 Transform
        Triggers/             WebhookTrigger
      Export/                 JsonExporter, CSharpCodeGenerator
      Templates/              ITemplateProvider, BuiltInTemplateProvider
      Extensions/             ServiceCollectionExtensions (DI registration)
    FlowForge.Web/            Blazor Server front-end
  tests/
    FlowForge.Core.Tests/     xUnit + FluentAssertions + Moq
    FlowForge.Web.Tests/

How it works:

1. The Visual Designer (Blazor) lets you place FlowNode objects on a canvas and connect them via FlowEdge objects.
2. Pressing Run sends the Workflow graph to the WorkflowEngine.
3. The engine walks the graph topologically, starting from nodes with no incoming edges.
4. Each node is resolved via NodeRegistry and executed through IFlowNode.ExecuteAsync.
5. Condition nodes route to true or false ports; loop nodes iterate and re-visit body nodes.
6. Execution traces stream back to the UI via IProgress<ExecutionTrace> for real-time feedback.

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Born From Production

"We needed an internal tool to let non-developers build data pipelines and approval workflows without writing code every time. FlowForge started as that tool -- and grew into something we think others can use too."

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What FlowForge Is NOT

	FlowForge	Enterprise BPM	No-Code Platforms
Target	.NET developers & small teams	Large enterprises	Non-technical users
Deployment	Self-hosted, single binary	Cloud / on-prem clusters	SaaS only
Customisation	Add C# nodes in minutes	XML/BPMN config files	Limited plugins
Cost	Free & open source	$$$$ per seat	$$$ per month
Overhead	Zero external dependencies	Message brokers, databases	Vendor lock-in

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Roadmap

• Visual drag-and-drop designer
• 10+ built-in node types
• Real-time execution with trace overlay
• JSON import / export
• C# code generation
• Demo templates
• Persistent workflow storage (SQLite / PostgreSQL)
• Authentication & role-based access
• Webhook listener for live triggers
• Custom node plugin system
• Workflow versioning & diff
• Parallel branch execution visualisation
• Debugging mode with breakpoints
• Real database & email integration

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Running Tests

dotnet test

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License

MIT -- Copyright (c) 2026 Mehmet Can Diri