How to Render Mermaid Diagrams (GitHub, VS Code, Web)
You wrote some Mermaid - now how do you see it? Here is every practical way to render Mermaid diagrams, from GitHub to your own website.
Writing Mermaid is only half the story; you need to render it to see the diagram. The good news is that Mermaid renders in an enormous range of places, from platforms that support it natively with zero effort to your own website with a few lines of code. This guide covers every practical rendering path - GitHub and GitLab, VS Code and other editors, live web editors, documentation systems, and self-hosted embedding - so whatever your setup, you know how to turn your Mermaid text into a picture.
The reason Mermaid renders so widely is that it is JavaScript that runs in the browser, so any platform can render it by including the Mermaid library, and many popular ones have built it in already. Whether you want a diagram in a README, in your editor as you write, in a docs site, or embedded in an app, there is a straightforward path. And if you want a live playground to write and immediately see Mermaid, the editor at /diagram-tools/mermaid-editor renders as you type.
GitHub, GitLab, and native platforms
The easiest rendering path is a platform that supports Mermaid natively, and the biggest is GitHub. To render a diagram in any Markdown file on GitHub - a README, an issue, a pull request comment, a wiki page - you put your Mermaid inside a fenced code block with `mermaid` as the language, like a triple-backtick block tagged `mermaid`. GitHub detects it and renders the diagram inline automatically. No setup, no extension, nothing to install; it just works.
GitLab supports the same thing with the same syntax, and so do a growing number of platforms - Notion, many wiki tools, and numerous documentation generators. This native support is a huge part of why Mermaid took over diagram-as-code: your diagram lives as text in the same file as your docs and renders wherever that file is displayed. The one thing to remember is the language tag on the code fence; without `mermaid` after the opening backticks, the platform shows your text as a plain code block instead of rendering it.
VS Code and local editors
When writing Mermaid locally, you want to preview as you go rather than pushing to GitHub to check. In VS Code, extensions add a live Mermaid preview: you write Mermaid in a Markdown file or a dedicated file, and a preview pane renders it beside your text, updating as you type. This tight feedback loop makes writing Mermaid much faster because you catch syntax errors and layout surprises immediately. Similar plugins exist for other editors like JetBrains IDEs, Vim, and Emacs.
Beyond editors, there are command-line tools. The Mermaid CLI lets you render a Mermaid file to a PNG or SVG image from the terminal or a build script, which is useful for generating diagram images automatically as part of a documentation build. This is how teams produce diagram images from text sources in continuous integration, so the rendered pictures in published docs always match the current text definitions without anyone manually exporting.
Web editors and quick rendering
For a quick render without any setup, live web editors are the fastest path. You paste or write Mermaid and see it rendered instantly in the browser, with no installation. These are ideal for drafting a diagram, checking that syntax is correct, or grabbing a quick image. The editor at /diagram-tools/mermaid-editor in Atlas Diagram Studio does exactly this, rendering as you type, and it goes further by letting you continue editing the result visually on the canvas at /diagrams - so you can start with Mermaid text and then fine-tune the layout by hand, which pure text renderers do not allow.
- GitHub and GitLab: fenced code block tagged `mermaid`, rendered natively, no setup.
- Notion and many wikis: native Mermaid support in code blocks.
- VS Code and other editors: extensions give live preview as you type.
- Mermaid CLI: render to PNG or SVG from the terminal or a build pipeline.
- Live web editors: paste and render instantly with nothing installed.
- Docs generators (many static-site tools): plugins render embedded Mermaid at build time.
- Your own site: include the Mermaid JavaScript library and it renders tagged blocks.
Embedding in your own site or app
To render Mermaid in a website or application you control, you include the Mermaid JavaScript library and initialize it, and it will render any element you have marked as containing Mermaid. This lets you build documentation sites, dashboards, or tools that display diagrams defined in text, with the diagrams rendering client-side in the visitor's browser. Because it is just JavaScript, it fits into essentially any web stack.
Many documentation frameworks and static-site generators have Mermaid integrations that handle this for you, rendering Mermaid code blocks in your Markdown at build time or in the browser. Whatever path you take, the core idea is consistent: Mermaid is text, and rendering is a matter of feeding that text to the Mermaid library, whether a platform does it for you or you wire it in yourself. When you need the rendered diagram as a shareable image or a polished export rather than an inline render, a tool like Atlas Diagram Studio lets you import the Mermaid and export clean PNG, SVG, or PDF from the canvas at /diagrams.