RWTH FSA Toolkit FSA is an efficient and flexible toolkit to create, manipulate and optimize finite-state automata. It supports weighted and unweighted automata as well as transducers and is designed to use on-demand computations in order to keep memory footprint as low as possible. It may be used to model various problems from the field of natural language processing. The toolkit offers three different interfaces: a C++ library, a Python module and a command-line tool. in Computational Linguistics > Finite Statewith finitefsafststate