The best alternatives to SimpleDiagrams are Wire Flow, Balsamiq, and Coggle. If these 3 options don't work for you, we've listed a few more alternatives below.
What do you think of SimpleDiagrams?
Tanka— Tanka = Slack + Glean, built for fast-growing startups.
The clear way to share complex information. Coggle is a collaborative mind-mapping tool that helps you make sense of complex things. Create unlimited mind maps and easily share them with friends and colleagues.
A better tool to help you draw technical designs, diagrams, scientific figures, flowcharts (and probably more). Vexlio is designed from the ground up with precision, ease-of-use, and high productivity diagramming in mind.
Smart auto-snapping means no more fussing with 1-pixel misalignments
| Tools like auto-create-grid are purpose built to make common tasks easy
| Integrated LaTeX equation support
| Syntax-highlighted code boxes
| Tons more
Web Sequence is a Chrome extension that saves your time and helps you avoid common mistakes when drawing sequence diagrams. You don't need to drag and drop or resize. Just type in your code (a DSL but like Java and C#) and a diagram is generated for you. Just added HTTPS support. If you are experience issues, please leave comments.