Is there an online mindmap that can be integrated in discourse?

[david (David Taylor)]

Have you looked at the graphviz plugin?

Graphviz Plugin

Summary: The Graphviz plugin allows you to add graphs to your post using the DOT language. GitHub: https://github.com/discourse/discourse-graphviz Install: Follow the plugin installation guide. Features This plugin uses the Viz.js library to render graphs. To embed a graph use [graphviz] [/graphviz] bbcode. Optionally you can define layout engine attributes: [graphviz engine=neato]. If engine is not defined, it defaults to the dot engine. See the Graphviz site for …

You can type this

[graphviz engine=circo]
graph {
    a [label="Discourse Plugins"]
    a -- "discourse-adplugin"
    a -- "discourse-affiliate"
    a -- "discourse-cakeday"
    a -- "discourse-canned-replies"
    a -- "discourse-calendar"
}
[/graphviz]

To make a graph like this: