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See it in action

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Why OpenFlowKit?

Every diagramming tool makes a compromise. OpenFlowKit doesn't.

Tool	What's missing
Excalidraw / tldraw	Freeform whiteboards — no structured diagram types, no DSL, no code imports
Mermaid.js	Code-only — no visual canvas, no AI, no interactive editor
Draw.io	Decade-old UX — Limited AI integration, no developer import pipelines
Lucidchart / Miro	Cloud lock-in — expensive, account required, your data lives on their servers
PlantUML	Server-dependent rendering — no visual editor, no local-first model

OpenFlowKit is the only MIT-licensed tool that combines a real workspace home, a professional visual canvas, bidirectional diagram-as-code, AI generation from 10 providers (including fully-local Ollama), automatic icon assignment from 1,600+ tech icons, anchored auto-layout, hardware-encoded cinematic MP4 export, and a Model Context Protocol server so Claude / Cursor / Windsurf can drive it directly — all with zero server-side storage.

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Feature highlights

	OpenFlowKit	Excalidraw	Draw.io	Mermaid	Lucidchart
Visual canvas editor	✅	✅	✅	❌	✅
Bidirectional diagram-as-code	✅	❌	❌	✅	❌
AI generation (10 providers + Ollama)	✅	❌	❌	❌	Limited
Mermaid import (8 types)	✅	❌	⚠️	✅	❌
Auto-icon assignment (1,600+)	✅	❌	❌	❌	❌
AWS / Azure / GCP / CNCF icons	✅	❌	✅	Partial	✅
Anchored auto-layout (pin nodes)	✅	❌	❌	❌	❌
Cinematic MP4 export (WebCodecs)	✅	❌	❌	❌	❌
Figma export (editable SVG)	✅	❌	❌	❌	❌
No account required	✅	✅	✅	✅	❌
Open source (MIT)	✅	✅	✅	✅	❌

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Paste Mermaid → Beautiful Diagrams

Paste any Mermaid flowchart, architecture, state diagram, class diagram, ER diagram, sequence diagram, mindmap, or journey — all 8 diagram families. OpenFlowKit renders it on a visual canvas and automatically assigns the correct branded icon to every technology node.

flowchart TD
  API[Express API] --> DB[(PostgreSQL)]
  DB --> Cache[Redis Cache]
  Cache --> Queue[RabbitMQ]

Paste this → you get the Express wordmark, PostgreSQL elephant, Redis logo, and RabbitMQ icon — all auto-detected, all beautifully laid out. No other tool does this.

1,600+ icons from developer, AWS, Azure, CNCF, and GCP catalogs are matched automatically based on node labels. No manual drag-and-drop. No configuration.

How it works

1. Paste Mermaid on the canvas or in the code panel
2. Semantic classifier detects technology names (PostgreSQL, Redis, Express, Lambda, etc.)
3. Icon matcher searches 1,600+ icons across all catalogs — exact match, then alias, then substring
4. Enricher assigns colors, icons, and provider SVGs to every node
5. ELK layout arranges everything cleanly

Mermaid quality gates

• npm run test:mermaid runs the broad Mermaid parser/plugin/round-trip gate
• npm run test:mermaid:layout runs the layout, import-state, and recovery corpus gate
• npm run test:mermaid:gold runs both together

AI generation (API key required)

Describe your system in plain English. AI generates a diagram on the canvas with correct icons applied automatically.

Prompt	Output
"Node.js API with PostgreSQL and Redis"	3 nodes with correct icons
"AWS Lambda → SQS → DynamoDB"	3 nodes with AWS icons
"React frontend → Express → MongoDB → S3"	4 nodes across developer + AWS catalogs

10 providers supported: Google Gemini, OpenAI, Anthropic Claude, Groq, Mistral, NVIDIA NIM, Cerebras, OpenRouter, Ollama (fully local), or any custom OpenAI-compatible endpoint. Bad DSL from any provider is now auto-repaired — the model sees its own broken output and the parser error, then returns corrected DSL in a single follow-up turn.

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Home first, editor second

OpenFlowKit now treats the product as two clear surfaces:

• Home for creating, opening, duplicating, importing, and organizing flows
• Editor for actual canvas work once a real document exists

That means the app does not create a fake default flow just to get you onto the canvas. If you delete everything, your workspace can stay empty until you intentionally create the next flow.

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Flowpilot — AI generation with any model

Flowpilot sits directly in the editor. Describe a system, paste source code, upload a screenshot, or ask it to refine what's already on the canvas. Your API key is stored in your browser and sent directly to the provider — OpenFlowKit's servers never see it.

10 providers. Bring your own key. Switch any time. One runs entirely on your laptop.

Provider	Default model	Why use it
🦙 Ollama (local)	llama3.2	Fully offline. No key, no network, no cost.
Google Gemini	gemini-2.5-flash-lite	Free tier available, fast, browser-safe
OpenAI	gpt-5-mini	Best reasoning for complex architectures
Anthropic Claude	claude-sonnet-4-6	Excellent code and system understanding
Groq	meta-llama/llama-4-scout-17b-16e-instruct	Fastest open-source inference available
Mistral	mistral-large-latest	Strong European privacy-first alternative
NVIDIA NIM	meta/llama-4-maverick-17b-128e-instruct	Enterprise GPU inference
Cerebras	gpt-oss-120b	Ultra-fast on WSE-3 silicon
OpenRouter	google/gemini-2.5-pro	Access 300+ models through one key
Custom endpoint	Any model	LM Studio, vLLM, or any OpenAI-compatible API

No proxy. No middleman. Direct browser-to-provider requests.

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OpenFlow DSL — diagram as code

Every diagram has a live code panel. Edit the canvas → code updates. Edit the code → canvas updates. Two-way, always in sync.

flowchart TB
  client[React App]   --> gateway[API Gateway]
  gateway             --> auth[Auth Service]
  gateway             --> orders[Orders Service]
  orders              --> db[(PostgreSQL)]
  orders              --> cache[(Redis)]
  auth                --> db

• Mermaid-compatible syntax — paste any Mermaid and it renders with auto-assigned icons
• Specify icons directly: { archProvider: "developer", archResourceType: "database-postgresql" }
• Auto-icon resolution: nodes are enriched with the correct branded icon based on their label
• Export to Mermaid, PlantUML, or JSON
• Version snapshots — restore any previous state

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Structured diagram families

Not a freeform whiteboard. Structured diagram types with opinionated defaults, correct relationship semantics, and purpose-built node styles.

• 🔷 Flowcharts — processes, decision trees, system flows
• ☁️ Architecture — AWS / Azure / GCP / CNCF cloud provider icons built in
• 🗄️ Entity-Relationship — typed fields, FK edges, one-to-many / many-to-many notation
• 📐 Class diagrams — UML with inheritance, composition, and interface relationships
• ↔️ Sequence diagrams — async messages, actors, and lifelines
• 🧠 Mind maps — collapsible radial trees with auto-layout
• 🛤️ User journeys — steps, phases, and sentiment scoring
• ⚙️ State machines — transitions, guards, entry and exit actions

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Editor workflow built for technical diagrams

OpenFlowKit works best when you move between the right surfaces instead of forcing everything through one panel:

• Toolbar add menu for quick insert actions
• Command Center for templates, import, assets, search, layout, pages, layers, and design systems
• Studio for Flowpilot, Mermaid, OpenFlow DSL, infra parsing, and linting
• Properties panel for exact visual and metadata edits

Large diagrams also get better organization with multi-page documents, layers, sections, and local-first document recovery.

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🎬 Cinematic Export — hardware-encoded MP4, no other OSS tool ships this

Turn any diagram into an animated video walkthrough — node by node, edge by edge — entirely in your browser. No upload, no server, no third-party tool.

Designed for architecture reviews, onboarding docs, and demos where a static image doesn't cut it.

No other open-source diagramming tool does this.

On modern browsers (Chrome / Edge / Safari 16.4+ / Firefox 130+) OpenFlowKit encodes via WebCodecs VideoEncoder + an in-browser MP4 muxer — H.264 baseline, hardware-accelerated, faster than real-time, deterministic frame timing. No more dropped frames under load. MediaRecorder remains a fallback for older browsers, so the feature is purely additive.

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🪄 MCP Server — drive OpenFlowKit from Claude Desktop, Cursor, Windsurf

Point any MCP client at the @vrun-design/openflowkit-mcp package and your AI assistant gains local-first diagramming tools — no API key, no cloud round-trip. Your client already has an LLM, so OpenFlowKit MCP supplies deterministic local validation, codebase analysis, templates, icon lookup, and viewer links.

{
  "mcpServers": {
    "openflowkit": {
      "command": "npx",
      "args": ["-y", "@vrun-design/openflowkit-mcp"]
    }
  }
}

Then ask Claude: "Read the OpenFlowKit DSL cheatsheet, create a checkout flow with a promo-code branch and a Stripe webhook step, validate it, and create a viewer URL." The DSL comes back in seconds and stays editable in OpenFlowKit.

• 8 local-first tools — validate DSL, create viewer URLs, analyze codebases, find icon slugs, fetch starter templates, and inspect capabilities (no API key, runs on your machine)
• 5 resources — DSL cheatsheet, template catalog, template bodies, full icon catalog, and per-provider icon catalogs
• 3 prompts — flowchart creation, Mermaid conversion, and codebase architecture, all using the client model
• Pure Node, zero infra cost — runs on the user's machine, ships via npm

Full setup, tool table, and workflow details in mcp-server/README.md.

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Export everywhere

Build your diagram once. Take it anywhere.

• 🎬 Cinematic WebM / MP4 — animated build walkthrough, browser-only, no upload required
• PNG / SVG — transparent background, pixel-perfect at any resolution
• PDF — print-ready, vector-crisp
• Mermaid — paste directly into GitHub READMEs, Notion, Confluence, Linear
• PlantUML — for enterprise toolchains and legacy integrations
• Figma — full editable SVG import with preserved layers
• JSON — complete round-trip import/export, no data loss

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Local-first by default — your data, your machine

Local-first is the default. Your saved flows live in your browser's IndexedDB. Your AI keys stay on your device — every request goes directly from your browser to the provider you chose. Exports are explicit and run entirely client-side. No accounts, no telemetry, no server-side storage.

Real-time P2P collaboration over WebRTC exists in the codebase as an opt-in beta (set VITE_COLLABORATION_ENABLED=true). It is off by default while we redesign the signaling path for production reliability — the local-first experience does not depend on it.

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Canvas built for keyboard-first developers

Shortcut	Action
⌘ K / Ctrl K	Command bar — search, import, layout, assets, and actions
⌘ \ / Ctrl \	Toggle the live code panel
⌘ Z / Ctrl Z	Full undo with complete history
⌘ D / Ctrl D	Duplicate selection
⌘ G / Ctrl G	Group selected nodes
P	Pin / unpin selected nodes (anchored layout)
⌘ / / Ctrl /	Keyboard shortcuts reference

Plus: smart alignment guides, snap-to-grid, multi-select, pages, layers, sections, architecture lint, light/dark/system theme, and full i18n in 7 languages.

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What we are improving next

Recently shipped (latest milestone):

• ✅ WebCodecs H.264 MP4 export — faster-than-realtime, hardware-accelerated, deterministic
• ✅ MCP server — @vrun-design/openflowkit-mcp for Claude Desktop, Cursor, Windsurf, any MCP client
• ✅ Anchored layout — pin nodes so auto-layout arranges around them
• ✅ Ollama provider — fully offline diagramming, no API key, no cost
• ✅ AI self-correction loop — bad DSL → AI sees its own output + parser error → returns corrected DSL
• ✅ ELK in a Web Worker — layout no longer blocks the UI thread
• ✅ Flowchart corpus 12 → 20 fixtures with explicit known-gap pinning

Current roadmap focus:

• render_to_svg MCP tool — headless SVG render so AI clients can see the diagram, not just code
• GIF export for cinematic animations — MP4 ships today; GIF export for zero-conversion embeds is next
• Mermaid family coverage — gantt, c4, timeline, gitGraph, sankey, quadrant (view + edit-as-code)
• Mac / Linux / Windows desktop app — Tauri shell wrapping the existing web app
• better layers and page workflows for larger technical diagrams
• smarter auto-layout defaults with less cleanup after import
• performance boosts for bigger canvases and heavier sessions

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Get started in 30 seconds

git clone https://github.com/Vrun-design/openflowkit.git
cd openflowkit
npm install
npm run dev

Open http://localhost:5173. Done.

Zero environment variables required. AI provider keys are configured in the in-app settings panel at runtime — nothing goes in .env.

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Self-host

OpenFlowKit is a pure static SPA. There is no backend. Deploy the dist/ folder anywhere that serves HTML.

Cloudflare Pages / Netlify / Vercel:

npm run build
# upload dist/ to your provider

Docker:

docker build -t openflowkit .
docker run --rm -p 3045:3045 openflowkit

Open http://localhost:3045. The container serves the production build with nginx, SPA route fallback, long-lived caching for hashed assets, and the same security headers used by the static hosting path.

No database. No secrets. No infrastructure. One folder, or one container.

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Tech stack

Layer	Technology
Framework	React 19 + TypeScript 5
Build	Vite 6
Canvas	React Flow (XYFlow)
Auto-layout	ELK.js — runs in a Web Worker, off the main thread
Video export	WebCodecs VideoEncoder + mp4-muxer (MediaRecorder fallback)
State	Zustand
Storage	IndexedDB — local-first, no backend
Styling	Tailwind CSS
Agent surface	@vrun-design/openflowkit-mcp — Model Context Protocol stdio
Collaboration	WebRTC P2P (opt-in, off by default)
i18n	react-i18next — 7 languages
Testing	Vitest + Playwright

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Contributing

All contributions are welcome — bug fixes, new diagram types, parser improvements, translations, and documentation.

Start here:

npm run dev        # development server at localhost:5173
npm run test       # unit tests via Vitest
npm run test:e2e   # end-to-end tests via Playwright
npm run lint       # ESLint + TypeScript type-check

Good first issues are tagged good first issue. Before opening a PR, please read CONTRIBUTING.md.

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