CoNTub is a software project written in Java which runs on Windows, Mac OS X, Linux and Unix Operating systems through any Java-enabled web browser.

It is the first implementation of an algorithm for generating 3D structures of arbitrary carbon nanotube connections by means of the placement of non-hexagonal (pentagonal or heptagonal) rings, also referred as defects or disclinations.

CoNTub is based on the strip algebra, and is able to find the unique structure for connecting two specific and arbitrary carbon nanotubes and many of the possible three-tube junctions.

CoNTub v2.0 has experimented a major redesign, and the panes have been removed, instead, a conventional menubar has been added where the type of structure to be generated can be chosen.

A further implementation of the Strip Algebra has been released in the second version of CoNTub, in order to elucidate the precise location of atoms and rings that lead to a junction of three nanotubes.