Beauty Diagram

About

Beauty Diagram re-renders Mermaid and PlantUML diagrams directly on the pages you already read. No copy-pasting and no separate tab — the improved diagram replaces the original right where it appears, and the original source stays one click away.

It runs automatically on its built-in supported sites, such as GitHub and GitLab, and you can switch it on for any other site — an internal wiki, a custom docs portal — from the popup with a single click. Raw code blocks that have not yet been rendered are never auto-processed: they show a small ◇ Render button so you decide which diagrams get beautified.

The rendering is done by the Beauty Diagram API (api.beauty-diagram.com), the same service behind the VS Code and Obsidian Beauty Diagram plugins. Only the diagram source text is sent — no page content, no browsing history, no personal data. An optional Pro API key removes the render watermark; it is stored only in your browser's local storage, never synced or logged.

Features
- In-place beautification — diagrams update on the page, no new tab needed
- ◇ Render opt-in button for raw code blocks (never auto-rendered)
- Automatic on built-in sites; per-site toggle for any other site via the popup
- Supports both Mermaid and PlantUML
- Theme selector and max-width control
- Original diagram source is always kept and accessible
- Optional Pro API key for watermark-free output
- No account required, no analytics, no ads