Free and open first
Best Diagramming tools in 2026
- 46 apps
- Research read 28 Sept 2026
- How the order is worked out
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Structurizr
by StructurizrFree plan Open source APILinuxMac+3Structurizr brings model-based architecture diagrams, multiple editing options, and export tools together. Check the per-installation user bands and hosting details against your team’s requirements.
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Sparx Enterprise Architect
by Sparx Enterprise ArchitectFree plan APILinuxMac+3Enterprise Architect combines modeling, requirements traceability, simulation, code engineering and collaboration in one tool.
- 5
Lucidchart
by LucidchartFree plan WebiPhoneAndroidChoose Lucidchart for a broad range of diagrams, real-time collaboration, offline editing, and connections to spreadsheet data.
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Eraser
Free plan APIExtensionSelf-hosted+1Eraser combines AI diagram creation with manual editing and team collaboration. The free plan is constrained, while private files and API calls begin with Starter.
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yEd Graph Editor
by yEd Graph EditorFree plan LinuxMacWindowsyEd offers broad diagram formats and layout options at no charge, with desktop versions for three operating systems.
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Mermaid
Free plan APIExtensionLinux+4Mermaid supports a broad range of diagram types and multiple ways to create, edit and share diagrams. Review the Basic tier’s limits and the stated browser or runtime requirements for your setup.
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Bizagi Modeler
by Bizagi ModelerFree plan WebWindowsBizagi Modeler combines BPMN modeling with simulation and multiple publishing routes, including a free single-user option.
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Software Ideas Modeler
by Software Ideas ModelerFree plan LinuxMacSelf-hosted+1Software Ideas Modeler brings broad diagram coverage together with code and database modeling tools. Its edition features vary, and real-time collaboration requires Software Ideas Server.
- 15
Visual Paradigm
by Visual ParadigmFree plan WebVisual Paradigm spans modeling, diagramming, and development tools, with browser and desktop workflows and collaboration options.
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ClickCharts
Free plan AndroidMacWindowsClickCharts covers a broad range of diagram types with templates, symbols, graphing, and export options.
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Graphviz
Free plan APILinuxMac+2Choose Graphviz if you want free, open-source graph visualization with configurable layouts and broad export options.
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Gliffy
Free plan WebGliffy covers varied diagram types, imports, exports and Confluence workflows, with a free option for smaller groups.
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Pencil Project
Free plan LinuxMacWindowsPencil combines interface-specific stencils, diagram shapes, and a range of export options in a desktop tool. Its links between document pages can carry through to web exports as hyperlinks.
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D2
Free plan APILinuxMac+3D2 offers text-based diagram creation with broad export, layout and editor options at no cost. Its documented scale limitation matters for very large diagrams.
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Dia
Free plan LinuxMacWindowsPick Dia if you need a free desktop diagrammer covering UML, flowcharts, networks, and entity relationships. Look elsewhere if you need a different platform or file-import route than those provided.
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#1Places #1, #2, #3, #4, #5 on this list can be bought by the makers of the software on it. See the price
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