draw.io is a free online diagram drawing application. You can use it to create UML, entity relationship, org charts, BPMN and BPM, database schema and networks. Also possible are telecommunication network, workflow, flowcharts, maps overlays and GIS, electronic circuit and social network diagrams. It's like a mini version of Visio in your browser.
You can export your diagram in our raw XML format, PNG or JPG, PDF or SVG and later re-load your saved XML.
If you are reading this, your browser might not be capable of displaying the application. The supported list of browsers is Firefox 3+, Microsoft Internet Explorer 7+, Safari 5+, Opera 9.0+, Camino 2+, Epiphany 2.0+, Galeon 2.0+ and Google Chrome 12+.