OpenFlowKit

What OpenFlowKit is

OpenFlowKit is a free, open-source diagram tool for the web. It supports both drag-and-drop editing and code-based diagram creation, so builders can work visually or define diagrams with its type-safe DSL or Mermaid.js syntax. It can parse JSON, React components, Prisma schemas, and SQL dumps into a diagram canvas. ELK.js auto-layout arranges nodes and routes edges.

Flowpilot AI lets users chat in natural language to build and style diagram blocks. AI generation requires the user's own OpenAI or Anthropic key; the site says those keys are stored on the user's device. OpenFlowKit describes its storage as local-first: diagrams stay on the user's machine, without cloud tracking or forced syncing. Users can share a link to collaborate through peer-to-peer WebRTC, with live cursors, and copy diagrams into Figma as editable SVG and text layers without a plugin.

The free plan costs nothing and includes unlimited diagrams and projects, with access to the core engine. Exports include PNG, JPG, SVG, JSON, Mermaid, PlantUML, WebM, MP4, and editable Figma output. The core engine is MIT licensed and can be hosted anywhere or modified. The project describes itself as just getting started, with the core engine being built in the open.

Who it suits

OpenFlowKit suits developers and other builders who want to turn code or schemas into diagrams, or create diagrams with drag-and-drop editing. It also fits people who need local-first diagram storage, live link-based collaboration, or editable Figma exports.

Limits

The free plan costs nothing and includes unlimited diagrams and projects with access to the core engine. AI generation requires the user's own OpenAI or Anthropic key.

Getting started

1. Open the OpenFlowKit website in a web browser.
2. Start with the free plan, which requires no account or credit card.
3. Create diagrams with drag-and-drop editing, supported code imports, the type-safe DSL, or Mermaid.js.
4. Provide your own OpenAI or Anthropic key if you want to use AI generation.
5. Share a link for peer-to-peer collaboration or export the diagram in a supported format.

Verdict

Choose OpenFlowKit if you want a free diagram tool that combines code imports, visual editing, and local-first storage. Its MIT-licensed core and broad export options also suit builders who want to host or modify the engine. Look elsewhere if you need AI generation without supplying your own provider key.