Sites and apps similar to Diagramo include draw.io, which is free and open source. Other options are Excalidraw, LibreOffice - Draw, yEd Graph Editor and Dia. Diagram Editors like Diagramo are a crowded field, with more than 50 alternatives for Windows, Mac, Linux, iPad and iPhone.
Grapholite is a powerful online solution for the creation of flowcharts, org charts, mind maps, Venn charts, web site structures, etc. Can be used online and offline
Ukraine
HotGloo is a UX, wireframe and prototyping tool designed to build wireframes for web, mobile and wearables. Create and share fully interactive prototypes with your team and clients and gather feedback on the process.
Germany
EU
Nevron Vision for .NET provides a complete set of components for data visualization that integrate with WinForms, Wpf, ASP.NET, and MVC applications.
BulgariaEU
Russia
FlairBuilder is a user interface prototyping tool for easy authoring of interactive website wireframes, mockups and GUI prototypes.
ConceptDraw DIAGRAM v14 is the only product that supports Visio legacy, runs on macOS and Windows, and is a perpetual license. Import/Export VDX, VSDX, VSSX and Import VSD, VSS files.
Ukraine
IYOPRO, Improve your Processes, is a professional online BPM and workflow system that utilizes the BPMN 2.0 standard.
Napkee makes your Balsamiq Mockups come alive. Import a BMML and export to web or flex code in a few clicks.
AustriaEU
Serena Prototype Composer - the best agile application prototyping tool is now free! View the demo, take the product tour, or download it free today.
MockupTiger is a web based application that helps you to build fluid wireframes, mockups or prototypes for your next web application or desktop software.
United States
Fluid UI is the fastest mobile app prototyping tool available. Design and test your low and high fidelity app mockups on a mobile device with ease. Simple and UX oriented, this UI tool helps unlock creativity and will save your team time and money while gathering app...
The GoVisual Diagram editor (GDE) provides powerful functionality for editing and automatic layout of diagrams. Diagrams are represented in form of graphs and cluster graphs. GDE contains all the layout styles available in the GoVisual libraries.
