Backend Breakdown

The backend is a Node.js server using Express. It manages flow execution, node orchestration, configuration, and data persistence.

Tech Stack

• Node.js

• Express

• TypeScript

• PostgreSQL or SQLite for storage

• Optional Redis for caching/memory

Folder Structure (Example)

bashCopyEdit/backend
  ├── api/                # Flow and node execution endpoints
  ├── nodes/              # Built-in and custom node logic
  ├── services/           # LLM providers, memory, tools
  ├── flows/              # Flow definitions and validation
  ├── database/           # DB connection + models
  └── utils/              # Error handling, logging, helpers

Core Backend Responsibilities

• Executing flows (resolving nodes in order)

• Managing inputs, outputs, and runtime memory

• Routing API requests from the frontend

• Validating flow structure and payloads

• Handling user data (if enabled)

• Storing flows and execution history in the database

Execution Flow

When a flow is triggered:

1. Input is received from chat or API

2. Flow graph is fetched and validated

3. Each node is executed in sequence, respecting dependencies

4. Outputs are returned, stored, or passed to downstream systems