UMLGraph
draw.io
Dia
LucidChart
yEd
OmniGraffle
UMLet
CollabNet
Getwebstack
MarsX
Getwebstack is for development teams that implement a lot of different projects. It can help outsourcing companies, accelerators, freelancers, or dev studios to develop fast. It is also for individuals that want to test a technology or an idea for a startup with a quick setup and deployment. Getwebstack provides a complete solution that covers all the technical aspects of a web app. It has an affordable monthly subscription instead of an expensive one-time payment.
UMLGraph
Getwebstackdraw.io - Online diagramming application
MarsX - MarsX leverages the power of AI to help users build mobile and web applications using code and no-code technology. MarsX is highly accessible, allowing even non-developers and those with zero building and coding experience to create their own mobile
Dia - Dia is a GTK+ based diagram creation program for GNU/Linux, MacOS X, Unix, and Windows, and is released under the GPL license.
LucidChart - LucidChart is the missing link in online productivity suites. LucidChart allows users to create, collaborate on, and publish attractive flowcharts and other diagrams from a web browser.
yEd - yEd is a free desktop application to quickly create, import, edit, and automatically arrange diagrams. It runs on Windows, Mac OS X, and Unix/Linux.
OmniGraffle - OmniGraffle is for creating precise graphics like website wireframes, an electrical system designs, or mapping out software class.