Extension:SimpleMermaid

**MediaWiki extensions manual**
SimpleMermaid; Release status: stable
Implementation	Tag
Description	Renders Mermaid diagrams in MediaWiki using the ‎<mermaid> tag
Author(s)	jmnote
Latest version	0.1.2 (2026-03-15)
MediaWiki	1.39+
Database changes	No
	Tags ‎<mermaid>
	Hooks used ParserFirstCallInit; OutputPageParserOutput;
Licence	Apache License 2.0
Download	GitHub: project page; git repository URL; commit history; ; ; README
Example	zetawiki.com

The SimpleMermaid extension renders diagrams with the Mermaid JavaScript library directly in MediaWiki pages.

It adds a ‎<mermaid>...‎</mermaid> tag for embedding Mermaid diagram source in wiki pages.

This extension loads Mermaid from a CDN at runtime, so client browsers must be able to access the external Mermaid bundle.

Features

Download and place the file(s) in a directory called SimpleMermaid in your extensions/ folder.
Add the following code at the bottom of your LocalSettings.php file:
```
wfLoadExtension( 'SimpleMermaid' );
```
Done – Navigate to Special:Version on your wiki to verify that the extension is successfully installed.

<mermaid>
flowchart TD
    A[Start] --> B{Decision}
    B -->|Yes| C[Do something]
    B -->|No| D[Do something else]
</mermaid>

Optional alignment:

<mermaid align="center">
graph LR
    A --> B
</mermaid>