OpenFlowKit

Need an architecture diagram or flowchart without signing up for anything? OpenFlowKit is a free, open-source diagram engine that lets you build diagrams by dragging shapes around a canvas or by writing them as code with Mermaid.js and a type-safe DSL.

It is made for engineers, architects and product teams.

The engine runs on React Flow and is local-first, so your data stays on your machine.

There is no account to create and no cloud sync to set up.

That is handy for teams who would rather not push internal system designs to a hosted service.

OpenFlowKit also includes an AI assistant called Flowpilot, which edits diagrams through chat, so you can describe a change instead of moving boxes by hand.

The Figma export is the most distinctive part.

It produces editable vector shapes rather than a flat image, which helps when a diagram has to be polished by a designer.

The whole tool is free to use.