GitPop
3 candidates

Open source alternatives to Lucidchart

Collaborative diagramming tool for flowcharts, UML, and ERDs. · Lucid Software, Inc.

Pricing: Free for individuals; paid from $8/user/mo

Lucidchart and draw.io (diagrams.net) are the default diagramming tools; the former is paid, the latter is open-source. The 2026 open-source path is to self-host draw.io (the OSS core of diagrams.net) or use Mermaid (Markdown-based, fits in your repo), Excalidraw (hand-drawn aesthetic), or Kroki (unified API for diagram-as-a-service). draw.io is the most direct Lucidchart replacement; Mermaid is the right pick for docs-first teams.

The 3 candidates, ranked by PopScore

  1. #01jgraph/drawio

    Open-source diagramming application that powers diagrams.net. The most direct Lucidchart replacement in 2026, with a self-hostable build.

    GitHub
  2. #02mermaid-js/mermaid

    Markdown-based diagramming that renders in the browser. The right pick for docs-first teams that want diagrams in their READMEs.

    GitHub
  3. #03excalidraw/excalidraw

    Virtual whiteboard with a hand-drawn aesthetic. The right pick for architecture diagrams and informal sketches.

    GitHub

Related alternatives

Looking for a side-by-side comparison of two open-source projects? The compare matrix has 60+ "X vs Y" pages. Looking for a curated "best of" list for a specific category? See Best AI tools 2026 (and the 7 other category editions).

Best open source alternatives to Lucidchart (2026) · GitPop