dayuan.jiang 1e4c74d464 feat(diagram-engine): edge router — pinned ports, obstacle avoidance, cost search
Fixes the reported problem: arrows overlapped on top of icons and ran through shapes
they had nothing to do with.

The cause was a missing layer, not a bug. render.ts emitted only source and target, so
draw.io routed every edge itself — and its router sees the two terminals' bounds and
nothing else, not where the other icons are. It therefore ran lines straight through
whatever was in between and left several edges leaving one node at the same point.

Ported from drawio-ai-kit's router (MIT, see NOTICE):

  - Port de-collision. Edges leaving the same side of the same node spread along it,
    ordered by where their far end sits so they do not cross on the way out. An edge
    with a clean straight shot keeps the centre.
  - Obstacle avoidance. Candidate shapes in order of directness — straight, a Z through
    the gap, an L, a two-bend detour — each tested against every icon on the page.
  - Frame placement. A frame is passable (an edge into a VPC must cross its border) but
    not free: running alongside a border, or cutting through a frame that holds only one
    of the two endpoints, is penalised.
  - Port snapping. On a bent route, each port moves to the side its leg actually arrives
    from. Without this the terminal segment can pierce the icon to reach a far-side port.
  - Lane claiming. Each routed edge records the lanes it occupies so later edges avoid
    them, rather than colliding and being pulled apart afterwards.
  - Global nudge, three passes, reverting any move that makes a path worse.

Two things I got wrong on the way, both caught by looking at real geometry:

  - The Z corridor was computed as min/max of both nodes' edges, which spans the whole
    distance between them — including anything parked in between. So the lane sweep
    would place the detour's middle leg on top of the very icon it was avoiding. It has
    to be the gap: trailing edge of the first node to the leading edge of the other.
  - The router was fed layout's slot rectangles, but an icon's cell is the glyph square
    centred in a slot roughly twice as wide. Collision tests against slots both missed
    real overlaps and invented false ones. Extracted cellRect() so the router and the
    emitted XML cannot diverge.

Accept-or-reject was not enough on its own. When one endpoint is inside a VPC and the
other outside, EVERY path trespasses on that frame, so the strict rule always fails and
the relaxed pass took whatever it tried first — which is how a line ended up cutting
across a whole VPC. Candidates are now scored (frame offences 500, lane sharing 700,
bends 80, length 1) and the cheapest wins, so an edge that must trespass still gets the
least-bad route.

Waypoints are still written only when load-bearing — a labelled bend or a deliberate
detour — so an unobstructed edge stays drag-friendly.

455 unit tests (27 new, asserting produced geometry rather than algorithm shape).
Verified by rendering the reported diagram in the real editor: the two arrows that
overlapped on the EC2 icon now leave from different sides, and the load balancer's
fan-out leaves from three distinct points.
2026-08-09 13:49:11 +09:00

Next AI Draw.io

AI-Powered Diagram Creation Tool - Chat, Draw, Visualize

English | 中文 | 日本語

TrendShift

License: Apache 2.0 Next.js React Sponsor

Live Demo

A Next.js web application that integrates AI capabilities with draw.io diagrams. Create, modify, and enhance diagrams through natural language commands and AI-assisted visualization.

Note: Thanks to ByteDance Doubao sponsorship, the demo site now uses the powerful glm-4.7 model!

https://github.com/user-attachments/assets/9d60a3e8-4a1c-4b5e-acbb-26af2d3eabd1

Table of Contents

Examples

Here are some example prompts and their generated diagrams:

Animated transformer connectors

Prompt: Give me a **animated connector** diagram of transformer's architecture.

Transformer Architecture with Animated Connectors
RAG Technique Diagram

Prompt: Generate a RAG architecture diagram for **chat application**. Use connected diagram for data ingestion

RAG Architecture Diagram
Authentication using React and AWS

Prompt: Generate authentication process using React with **AWS**. Use Serverless architecture.

Authentication Architecture Diagram
Open Innovation

Prompt: Create visualization of Henry Chesbrough's Open Innovation model.

Open Innovation Diagram
Cat sketch

Prompt: Draw a cute cat for me.

Cat Drawing

Features

  • LLM-Powered Diagram Creation: Leverage Large Language Models to create and manipulate draw.io diagrams directly through natural language commands
  • Image-Based Diagram Replication: Upload existing diagrams or images and have the AI replicate and enhance them automatically
  • PDF & Text File Upload: Upload PDF documents and text files to extract content and generate diagrams from existing documents
  • AI Reasoning Display: View the AI's thinking process for supported models (OpenAI o1/o3, Gemini, Claude, etc.)
  • Diagram History: Comprehensive version control that tracks all changes, allowing you to view and restore previous versions of your diagrams before the AI editing.
  • Interactive Chat Interface: Communicate with AI to refine your diagrams in real-time
  • Cloud Architecture Diagram Support: Specialized support for generating cloud architecture diagrams (AWS, GCP, Azure)
  • Animated Connectors: Create dynamic and animated connectors between diagram elements for better visualization

MCP Server

Use Next AI Draw.io with AI agents like Claude Desktop, Cursor, and VS Code via MCP (Model Context Protocol).

{
  "mcpServers": {
    "drawio": {
      "command": "npx",
      "args": ["@next-ai-drawio/mcp-server@latest"]
    }
  }
}

Claude Code CLI

claude mcp add drawio -- npx @next-ai-drawio/mcp-server@latest

Then ask Claude to create diagrams:

"Create a flowchart showing user authentication with login, MFA, and session management"

The diagram appears in your browser in real-time!

See the MCP Server README for VS Code, Cursor, and other client configurations.

Getting Started

Try it Online

No installation needed! Try the app directly on our demo site:

Live Demo

Bring Your Own API Key: You can use your own API key to bypass usage limits on the demo site. Click the Settings icon in the chat panel to configure your provider and API key. Your key is stored locally in your browser and is never stored on the server.

Desktop Application

Download the native desktop app for your platform from the Releases page:

Supported platforms: Windows, macOS, Linux.

Run with Docker

Go to Docker Guide

Installation

  1. Clone the repository:
git clone https://github.com/DayuanJiang/next-ai-draw-io
cd next-ai-draw-io
npm install
cp env.example .env.local

See the Provider Configuration Guide for detailed setup instructions for each provider.

  1. Run the development server:
npm run dev
  1. Open http://localhost:6002 in your browser to see the application.

Deployment

Deploy to EdgeOne Pages

You can deploy with one click using Tencent EdgeOne Pages.

Deploy by this button:

Deploy to EdgeOne Pages

Check out the Tencent EdgeOne Pages documentation for more details.

Additionally, deploying through Tencent EdgeOne Pages will also grant you a daily free quota for DeepSeek models.

Deploy on Vercel

Deploy with Vercel

The easiest way to deploy is using Vercel, the creators of Next.js. Be sure to set the environment variables in the Vercel dashboard as you did in your local .env.local file.

See the Next.js deployment documentation for more details.

Deploy on Cloudflare Workers

Go to Cloudflare Deploy Guide

Multi-Provider Support

  • ByteDance Doubao
  • AWS Bedrock (default)
  • OpenAI
  • Anthropic
  • Google AI
  • Google Vertex AI
  • Azure OpenAI
  • Ollama
  • OpenRouter
  • AIHubMix
  • DeepSeek
  • SiliconFlow
  • ModelScope
  • SGLang
  • Vercel AI Gateway

All providers except AWS Bedrock and OpenRouter support custom endpoints.

📖 Detailed Provider Configuration Guide - See setup instructions for each provider.

Server-Side Multi-Model Configuration

Administrators can configure multiple server-side models that are available to all users without requiring personal API keys. Configure via AI_MODELS_CONFIG environment variable (JSON string) or ai-models.json file. For a single-provider quick setup, list comma-separated model IDs in AI_MODEL.

Admin Panel

Set the ADMIN_PASSWORD environment variable and visit /admin to manage server settings (models, access codes, features, observability, quota) from a web panel instead of hand-editing .env.

📖 Admin Panel Guide — setup, precedence rules, and notes.

Model Requirements: This task requires strong model capabilities for generating long-form text with strict formatting constraints (draw.io XML). Recommended models include Claude Sonnet 4.5, GPT-5.1, Gemini 3 Pro, and DeepSeek V3.2/R1.

Note that the claude series has been trained on draw.io diagrams with cloud architecture logos like AWS, Azure, GCP. So if you want to create cloud architecture diagrams, this is the best choice.

How It Works

The application uses the following technologies:

  • Next.js: For the frontend framework and routing
  • Vercel AI SDK (ai + @ai-sdk/*): For streaming AI responses and multi-provider support
  • react-drawio: For diagram representation and manipulation

Diagrams are represented as XML that can be rendered in draw.io. The AI processes your commands and generates or modifies this XML accordingly.

Support & Contact

Special thanks to ByteDance Doubao for sponsoring the API token usage of the demo site! Register on the ARK platform to get 500K free tokens for all models!

If you find this project useful, please consider sponsoring to help me host the live demo site!

For support or inquiries, please open an issue on the GitHub repository or contact the maintainer at:

  • Email: me[at]jiang.jp

FAQ

See FAQ for common issues and solutions.

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Description
A next.js web application that integrates AI capabilities with draw.io diagrams. This app allows you to create, modify, and enhance diagrams through natural language commands and AI-assisted visualization.
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