Draw. IO is a powerful and concise online drawing site that supports diagrams, UML diagrams, architecture diagrams, prototypes, and more. Support Github, Google Drive, One Drive and other network disk synchronization, and permanent free. If you find the Web version inconvenient, draw. IO also offers a multi-platform offline desktop version for download.
The web version
app.diagrams.net/
The desktop version
Github.com/jgraph/draw…
Github.com/jgraph/draw…
Similar product processon
www.processon.com/