Flowchart Maker & Online Diagram Software Flowchart Maker and Online Diagram Software draw.io is free online diagram software. You can use it as a flowchart maker, network diagram software, to create UML online, as an ER diagram tool, to design database schema, to build BPMN online, as a circuit diagram maker, and more. draw.io can import .vsdx, Gliffy™ and Lucidchart™ files . Loading... Please ensure JavaScript is enabled.