  We introduce a graphical user interface for constructing arbitrary tensor
networks and specifying common operations like contractions or splitting,
denoted GuiTeNet. Tensors are represented as nodes with attached legs,
corresponding to the ordered dimensions of the tensor. GuiTeNet visualizes the
current network, and instantly generates Python/NumPy source code for the
hitherto sequence of user actions. Support for additional programming languages
is planned for the future. We discuss the elementary operations on tensor
networks used by GuiTeNet, together with high-level optimization strategies.
The software runs directly in web browsers and is available online at
http://guitenet.org.
