I Built an AI Diagramming Tool You Can Talk To — And Released It for Free
Talk to your diagrams. They listen.
I've been drawing architecture diagrams for a long time. Boxes, arrows, layers, swimlanes — the visual language of how systems actually work. I'm reasonably fast at it. But fast is still slow when what you really want is to say 'add a caching layer between the API gateway and the database' and just have it happen. That's the thing I kept wanting. It eventually led me to build DiagramForge.
The Problem with Diagramming Tools
Most diagramming tools treat you like a graphic designer. You drag shapes. You draw arrows. You align boxes. You spend twenty minutes making a diagram look right that took you five minutes to think through. The intelligence is yours. The tool is just a canvas. That's fine for polished deliverables. It's friction for everything else — the working diagram you're iterating on, the architecture you're explaining to a team, the flow you're capturing before you forget it.
What DiagramForge Does
DiagramForge connects an AI chat interface directly to a live draw.io canvas. You describe what you want. The diagram updates. You keep talking. It keeps updating. The full draw.io editing experience is still there when you want it — you can drag, resize, restyle anything the AI produces. But the primary loop is conversation, not clicking.
- C4 architecture diagrams — context, container, and component levels
- Cloud architecture — AWS, Azure, GCP service layouts with labeled flows
- Flowcharts and process diagrams — business logic, decision trees, approval flows
- Sequence diagrams — system interactions, API call chains, event flows
- ER and data model diagrams — entity relationships, schema visualizations
- Any draw.io diagram — if draw.io can render it, DiagramForge can generate it
Multi-Provider AI — Bring Your Own Key
DiagramForge doesn't lock you into one AI provider. It supports every major one: Google Gemini, OpenAI, Anthropic Claude, Ollama (local models), Azure OpenAI, AWS Bedrock, DeepSeek, and OpenRouter. Your API key is stored locally on your machine. Nothing passes through any server I control. You configure it once in settings — provider, model, key — and the rest works. If you already pay for Gemini or Claude for other work, DiagramForge just uses that. No additional subscription.
- Google Gemini — gemini-2.5-pro and other Gemini models
- Anthropic Claude — claude-sonnet, claude-opus
- OpenAI — GPT-4o, GPT-4 Turbo
- Ollama — run fully offline with local models (llama3, mistral, etc.)
- Azure OpenAI, AWS Bedrock, DeepSeek, OpenRouter — all supported
Built on Open Source
DiagramForge is built on two Apache 2.0 open-source foundations: draw.io by JGraph — the industry-standard diagramming engine used by millions — and next-ai-draw-io by DayuanJiang, which pioneered the idea of connecting an AI chat interface to a draw.io canvas. I built on that foundation: added multi-provider AI support, hardened the provider switching, added desktop packaging via Electron, and made it work fully offline. All three layers — draw.io, next-ai-draw-io, and DiagramForge — are Apache 2.0. Free to use, free to inspect, free to build on.
Builder Notes
A few things I learned building this that are worth saying out loud. First: AI-generated diagrams are a starting point, not a deliverable. The quality of what comes out depends heavily on how specific you are. 'Draw a microservices architecture' produces something generic. 'Draw a microservices architecture with an API gateway, three backend services (auth, order, inventory), a shared Postgres database, and a Redis cache between the API gateway and auth service' produces something actually useful. Second: the best AI providers for diagram generation, in my experience, are the ones with strong instruction-following — Gemini 2.5 Pro and Claude Sonnet 3.7 both handle complex draw.io XML reliably. Third: this works best when you iterate. Start with a rough shape and refine it conversationally. 'Move the database to the right side.' 'Add an arrow from the API gateway to the cache.' 'Label that flow with the HTTP method.' It gets where you want faster than starting over.
Download DiagramForge — Free
DiagramForge v1.0.2 is free for personal and commercial use. No subscription, no account required, runs 100% offline once installed. Windows and macOS installers are both available now.
What's Coming Next
DiagramForge v1.0.2 is a solid starting point. The road ahead:
- macOS installer with proper code signing
- Diagram templates — C4 starter, AWS reference architecture, microservices baseline
- Export improvements — higher-res PNG, SVG, and PDF exports directly from chat
- Context-aware editing — reference specific shapes by name in your prompt
- DiagramForge Pro — for teams, with shared diagram libraries and multi-user sessions
Takeaway
The best diagram is the one that exists. I've watched too many architecture decisions get made in Slack because nobody had time to open Visio and draw the thing. DiagramForge is for those moments — where the bottleneck isn't your thinking, it's the gap between thought and canvas. If you try it, I'd genuinely like to know what you think. Open an issue, send a note, or just tell me what's missing.