テキストから図へ。 AI が描く、あなたの端末の中で。
無料の AI フローチャート・マインドマップ作成ツール。欲しい図をふつうの言葉で説明するだけ。端末内の小さなモデルが Mermaid コードを書き、きれいな図をその場で描画します。アップロードなし、登録不要、SVG または PNG で書き出し。
一文から、数秒で図に。
端末内の言語モデルが Mermaid を代わりに書きます。プロンプトがブラウザの外に出ることはありません。
100% オンデバイス & プライベート
図の生成はすべてブラウザ内で行われます。Chrome の組み込み AI、またはローカルの Qwen 1.5B モデルを使用。プロンプトがサーバーに送信されることは一切ありません。
8 種類の図に対応
フローチャート、マインドマップ、シーケンス、クラス、ステート、ER、ガント、Git グラフ。種類を選ぶことも、プロンプトからモデルに判断させることもできます。
ストリーミングでライブ描画
図がトークンごとに描かれていく様子をそのまま見られます。Mermaid はストリーミング中に解析・描画されるため、形がリアルタイムに立ち上がり、そのままコードを修正できます。
編集・書き出し・自分のものに
生成された Mermaid コードは自由に編集できます。ノードやエッジを調整し、くっきりした SVG ベクター、または最大 4 倍の高解像度 PNG で書き出し。有料の壁で囲まれた機能はありません。
説明する。生成する。仕上げる。
- 01
図を説明する
一文を書くか、仕様を貼り付けます。「ユーザー登録とオンボーディングの流れ」「EC サイトのデータベース構成」「アジャイルスプリントのワークフロー」。図の種類を選ぶことも、モデルに任せることもできます。
- 02
描かれていくのを見る
端末内のモデルが、正しい Mermaid を 1 行ずつ書き出します。キャンバスがライブで描画し、よくある構文のミスはストリーミング中に検出して修復します。
- 03
編集して書き出す
エディタで Mermaid コードを直接編集 — ノードの追加、エッジのラベル変更、テーマの切り替え。ベクター用途なら SVG、最大 4 倍の解像度なら PNG で書き出せます。
About the AI diagram generator
Diagram Studio is a free AI flowchart and mindmap generator that runs entirely in your browser. Describe what you want — a signup flow, a database schema, a sprint workflow, a release branching strategy — and a small on-device language model writes the Mermaid code, renders it live as it streams, and lets you refine the result in a code editor before exporting as SVG or PNG.
It is built for the situations where cloud diagram tools are the wrong answer: drafting a quick sequence diagram from a meeting note, generating a private ER schema for a client system you cannot put on someone else's server, or producing a publishable flowchart without signing up for anything. Nothing leaves your device.
How it works
Two engines sit behind the same interface. The first is Chrome's built-in AI (the LanguageModel API, available in Chrome 127+ and other Chromium browsers that ship Gemini Nano). It runs the model the browser already has embedded, so there is nothing to download — generation starts immediately and stays on-device. The second engine is a local Qwen2.5 1.5B model loaded through Transformers.js on WebGPU (with a WebAssembly fallback when WebGPU is unavailable). It is a one-time download of roughly 1 GB, cached by the browser for offline use afterwards.
Whichever engine runs, the output is a Mermaid code block. A small regex-based auto-fixer repairs the common slips a 1.5B model makes — unbalanced subgraph ends, missing diagram-type keywords, unclosed quotes in node labels — before the code reaches the renderer. Mermaid then parses and renders the code, with a streaming-tolerant mode that silently ignores mid-generation syntax errors and a final render that surfaces real errors with a clear message.
Diagram types and themes
Eight diagram types are supported: flowchart, mindmap, sequence, class, state, entity-relationship, Gantt and git graph. You can pin a type explicitly, or leave the selector on Auto and let the model pick the most appropriate representation from your prompt — a request about "database tables" tends to land on an ER diagram, a request about "user journey" on a flowchart, a request about "message exchange" on a sequence diagram.
Four built-in Mermaid themes (Default, Neutral, Dark, Forest) recolour the rendered diagram instantly without re-running the model. The code itself is theme-agnostic, so you can switch themes mid-edit without losing your work.
Editing and export
The Mermaid code is always exposed in an editor next to the canvas. Every keystroke re-renders the diagram live. You can rename nodes, rewire edges, add subgraphs, swap the diagram type, fix a label the model got wrong — the editor is the source of truth, not a read-only artifact.
Export supports SVG (vector, infinite resolution, ideal for web and print) and PNG at 2× or 4× raster resolution. Both are generated client-side from the rendered SVG via canvas rasterization — no server round-trip, no watermark, no account. SVG preserves interactivity and scales cleanly into a documentation site or a slide deck; PNG is the right choice when you need a single self-contained image for chat, email or a slide.
Limits & requirements
The local Qwen model needs a reasonably modern device for acceptable speed — WebGPU support matters, and 1.5B parameters still means a multi-second generation for a complex flowchart. The Chrome built-in AI path is faster when available but only exists on Chromium browsers that ship Gemini Nano. If neither is available, the tool still works as a pure Mermaid editor: write the code by hand, get live rendering and the same export options.
A 1.5B model is not a frontier model. It will occasionally produce a syntactically wrong construct that the auto-fixer cannot repair, or mislabel a node. The live editor exists precisely for this case — treat the AI output as a first draft, not a final artifact. For diagrams with strict semantic requirements (UML compliance, BPMN naming), expect to do some manual cleanup.
Privacy
Your prompt and the generated Mermaid code never leave your browser. There is no server-side generation, no logging, no analytics on the prompt content, and no account. The only network request the tool ever makes is the one-time model download from a CDN — and once the model is cached, even that goes away. The built-in AI path makes no network requests at all.