The best alternative to Dia is Excalidraw, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 50 alternatives to Dia and many of them are so hopefully you can find a suitable replacement. Other interesting alternatives to Dia are LibreOffice - Draw, yEd Graph Editor, PlantUML and Square Sketch.
Excalidraw is an open-source whiteboard tool that lets you easily sketch diagrams that have a hand-drawn feel to them. Available directly online as a web app and also through CodeSandbox to easily see how the code works, and the app is available for self-hosting.
Czechia
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Draw lets you produce anything from a quick sketch to a complex plan, and gives you the means to communicate with graphics and diagrams. With a maximum page size of 300cm by 300cm, Draw is a an excellent package for producing technical drawings, general posters, and much else.
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yEd is a powerful diagram editor that can be used to quickly create diagrams manually or import external data for analysis and auto-magically arrange even large data sets by just pressing a button. You can use yEd to quickly create flow charts, BPMN and UML diagrams...
GermanyEU
PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams. The generator can be run anywhere within JVM and integrated with various application such as wiki, text editor, IDE, programming language, documentation generator, and others.
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Mindomo is the easiest online software for creating mind maps, concept maps, outlines and various other types of diagrams. The following features make it the perfect choice both for business and education:
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Gaphor is a WYSIWYG (What You See Is What You Get) UML and SysML modeling environment easy to use that will help you create your applications.
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Umbrello is a Unified Modelling Language (UML) modelling tool and code generator. It can create diagrams of software and other systems in the industry-standard UML format, and can also generate code from UML diagrams in a variety of programming languages.
GermanyEU
Lightweight, powerful, easy to use, UML tool
Software Ideas Modeler is a lightweight and powerful CASE tool. It supports UML 2.2 diagrams and a lot of other ones. Software Ideas Modeler is freeware (for non-commercial use). Commercial user may use this software only after buying.
SlovakiaEU
MyDraw is an easy to use, yet powerful diagramming software that lets you create a large number of diagrams like flowcharts, organizational charts, mind maps, network diagrams, floor plans, family trees, business model diagrams, and many more.
BulgariaEU
ARIS Express is based on the proven ARIS methodology and industry standards. Its intuitive user interface and the latest improvements in modeling assistances enable instant results. This free version will appeal to universities and vocational schools, as well as BPM beginners...
GermanyEU
Simple vector graphics editor for creating flowcharts, UML class diagrams, illustrations and slide shows.
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