This is the backend service for the Full Stack Node Editor project.
It is built with FastAPI and provides APIs for validating and processing node-based pipelines.

• FastAPI server with CORS enabled (frontend at http://localhost:5173).
• Pipeline validation endpoint:
  • Accepts a list of nodes and edges.
  • Runs a DAG (Directed Acyclic Graph) check using Kahn’s Algorithm.
  • Detects cycles in the pipeline graph.
• Ready to integrate with the frontend editor.

• Python 3.9+
• Dependencies listed in requirements.txt

Install them:

pip install -r requirements.txt

Start the backend locally with:

uvicorn main:app --reload

The API will be available at:

http://127.0.0.1:8000

Simple health check.

Response

{ "Ping": "Pong" }

Validate a pipeline by checking if it is a valid DAG.

Request Body

{
  "nodes": [
    { "id": "1", "type": "Start", "position": { "x": 0, "y": 0 }, "data": {} },
    {
      "id": "2",
      "type": "Task",
      "position": { "x": 100, "y": 100 },
      "data": {}
    }
  ],
  "edges": [{ "id": "e1-2", "source": "1", "target": "2" }]
}

Response

{
  "num_nodes": 2,
  "num_edges": 1,
  "is_dag": true,
  "message": "Pipeline is valid and ready for execution."
}

• CORS allows requests from the frontend (http://localhost:5173).
• Modify origins in main.py to allow other clients.
• Future extension: Add execution engine for pipelines.