This paper introduces the Kodo network coding library. Kodo is an open source C++ library intended to be used in practical studies of network coding algorithms. The target users for the library are researchers working with or interested in network coding. To provide a research friendly library Kodo provides a number of algorithms and building blocks, with which new and experimental algorithms can be implemented and tested. In this paper, the authors introduce potential users to the goals, the structure, and the use of the library. To demonstrate the use of the library they provide a number of simple programming examples.