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Mermaid alternatives · Whiteboards

Open-source alternatives to Mermaid

Mermaid is not described as open source on its own site. 6 of the 61 other whiteboard and mind map tools in this directory are open source, according to their own sites.

Mermaid has a free plan. Paid plans start at $10 per user / month, billed annually ($120 a year). All of them are free or have a free plan.

6 tools · Listings checked up to Nov 12, 2026 · Where the facts come from

How each one differs from Mermaid

  1. draw.io

    Free diagram editor that saves files to storage you choose

    • draw.io is free. Mermaid starts at $10 per user / month, billed annually ($120 a year).
    • Only draw.io lists macOS, Windows and Linux apps.
    • draw.io is open source and self-hostable, according to its own site.
    • draw.io also covers templates.
    draw.io vs Mermaiddraw.io pricing and details

  2. Excalidraw

    Open-source whiteboard for hand-drawn style sketches and diagrams

    • Excalidraw starts at $6 per user / month, billed annually. Mermaid starts at $10 per user / month, billed annually ($120 a year).
    • Excalidraw is open source, self-hostable and end-to-end encrypted, according to its own site.
    • Excalidraw also covers whiteboard.
    • Mermaid also covers presentations.
    Excalidraw vs MermaidExcalidraw pricing and details

  3. Flowchart Fun

    Text-based flowchart maker that draws diagrams as you type

    • Flowchart Fun starts at $2 per month (billing basis not stated). Mermaid starts at $10 per user / month, billed annually ($120 a year).
    • Flowchart Fun is open source, according to its own site.
    • Flowchart Fun also covers mind mapping.
    • Mermaid also covers presentations.
    Flowchart Fun vs MermaidFlowchart Fun pricing and details

  4. PlantUML

    Draw UML and other diagrams from plain-text descriptions

    • PlantUML is free. Mermaid starts at $10 per user / month, billed annually ($120 a year).
    • Only PlantUML lists a browser extension.
    • PlantUML is open source, according to its own site.
    • PlantUML also covers Gantt & timelines and mind mapping.
    PlantUML vs MermaidPlantUML pricing and details

  5. Freeplane

    Free, open source mind mapping app for the desktop

    • Freeplane is free. Mermaid starts at $10 per user / month, billed annually ($120 a year).
    • Only Freeplane lists Windows, macOS and Linux apps.
    • Only Mermaid lists a web app.
    • Freeplane is open source, according to its own site.
    Freeplane pricing and details

  6. OpenBoard

    Free open-source interactive whiteboard software for classrooms

    • OpenBoard is free. Mermaid starts at $10 per user / month, billed annually ($120 a year).
    • Only OpenBoard lists Windows, macOS and Linux apps.
    • Only Mermaid lists a web app.
    • OpenBoard is open source, according to its own site.
    OpenBoard pricing and details

Common questions

Is there an open-source alternative to Mermaid?

Yes. draw.io, Excalidraw, Flowchart Fun, PlantUML, Freeplane and OpenBoard are open source, according to their own sites.

Is Mermaid open source?

Mermaid is not described as open source on its own site. The listing was checked on Oct 6, 2026 against the pages it cites.

When was this checked?

Each listing shows its own date. On this page they run from Oct 5, 2026 to Nov 12, 2026. Vendors change prices and plans without notice, so confirm on their site before you buy.

This page is built from the listings. A tool is here because its listing says so, and the order is how close each is to Mermaid: the alternatives its listing names first, then the tools that share the most features with it.