Dia is an open source tool for making different kinds of diagrams and flowcharts.

It is of modular design and thus has several shape packages available, such as flowcharts, network diagrams and circuit diagrams. It's also possible to add support for new shapes by writing an XML file using a subset of SVG. Dia can also be scripted using Python.

As default, Dia saves diagrams to a custom, packaged XML format. It can however export them to various formats, including EPS, SVG, DXG, CGM, WMF, PNG, JPEG and VDX. Diagrams, even large multi-page ones, can also be printed.