Diagramming
draw.io
Open source diagramming tool with real-time collaboration and privacy-first data storage.
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6+ Free Diagramming Tools
7 of the 7 tools in this category have a free plan. 2 are completely free and 5 offer a free tier beside paid plans.
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Diagramming tools with a free plan
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Diagramming
Mindomo
Mindomo is a collaborative mind mapping tool supporting mind maps, concept maps, outlines, and Gantt charts with real-time editing and AI
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Diagramming
PlantUML
An open-source tool that generates UML and other diagrams from simple textual descriptions.
Diagramming
MindMeister
MindMeister is an online mind mapping tool for brainstorming, organizing, and collaborating on ideas in real time.
Diagramming
gliffy
Gliffy is a cloud-based diagramming tool integrated with Atlassian Confluence and Jira for creating and sharing professional diagrams.
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Frequently asked questions
How many Diagramming tools are there?
Siteefy's live index currently tracks 7 Diagramming tools, with 7 added in 2026. The count updates automatically as tools are published or retired.
Are there free Diagramming tools?
Yes. 2 of the 7 tools are completely free and 5 offer a free plan alongside paid tiers.
How is this Diagramming list ordered?
Boosted listings appear first, then the most reviewed tools, then the most saved and highest rated. Star ratings come from community reviews, and anyone can review a tool or suggest one that is missing.