Most AI diagram tools want a complete prompt. This one takes a rough idea, asks what's missing, suggests what to include, draws, and then keeps revising as you talk. 8 diagram types, EN/ZH, free to try.

Free AI-powered Mermaid diagram generator. Describe your flow, database schema, or API in plain English — AI writes the Mermaid syntax, you get an editable diagram to export as SVG or PNG. No signup, no watermark.