MindSpark is an open-source, self-hostable mind-mapping application developed in vanilla JavaScript and distributed under the MIT license. It represents each map as a Markdown outline and keeps the canvas and Markdown editor synchronized in both directions, with imports and exports for formats including JSON, OPML, Markdown, PNG, PDF, Word, Mermaid, and GitMind.
The editor provides automatic tree layout, drag-and-drop reordering, rich-text nodes, LaTeX rendering through MathML, an Excel-like node formula engine with functions such as SUM, AVERAGE, IF, ROUND, and SQRT, version history, read-only URL share links, and citations with DOI-based metadata retrieval from Crossref. Research, prompt-engineering, software, and AI-agent templates are included; map branches can also be compiled into prompts for Anthropic or OpenAI using a user-supplied API key.
MindSpark can run locally with Node.js and SQLite, as a static site using a personal access token to save maps in a user's own Git repository, or with an optional Cloudflare Worker for OAuth, editable shared maps, access control, and real-time collaboration. Its repository also describes a separate MCP server for creating, reading, editing, and rendering maps through compatible AI clients.