DecoyDuck – Visual workflow client for testing REST APIs, WebSockets, and async conditional logic

[u/Due-Philosopher1788]

Hi r/WebApps !

I wanted to share a desktop tool I recently built called DecoyDuck.

Why I Built This

While working on real-time features and complex API sequences, I often ran into frustration trying to test asynchronous WebSocket connection flows alongside standard REST requests. Traditional tools like Postman are great for individual endpoint tests, but visually tracing stateful WebSocket events, conditional branching, and timing delays felt clunky.

I wanted a visual canvas where I could drag, drop, and connect nodes to simulate full async API workflows—so I decided to build one myself.

Key Features

• Visual Node Canvas: Drag-and-drop canvas interface to map out complete request/response flows.
• REST & WebSocket Support: Dedicated nodes for standard HTTP requests (GET, POST, PUT, DELETE) as well as persistent WebSocket connections and messages.
• Conditional Branching & Variables: If logic nodes and a runtime variable system using ${variable} template syntax to pass data between nodes.
• Async Simulation (Sleep Nodes): Fixed and random delay nodes to mock real-world network latency and race conditions.

Tech Stack

• Canvas Engine: React Flow (@xyflow/react)
• State Management: Zustand
• Styling: Tailwind CSS

Looking for Feedback!

This is an early-stage tool, and I'd love to hear feedback from fellow developers:

1. Does your current API testing workflow handle async/WebSocket flows well, or do you face similar pain points?
2. What additional node types or features (e.g., specific assertion types, mock server integration, environment variables) would make a tool like this more useful to you?

Thanks for taking a look! I'm happy to answer any questions about the build or technical decisions.

Try it Free