IFEFFIT is a computer program and callable library for XAFS analysis. It provides an interactive session for reading, manipulating and viewing EXAFS data. IFEFFIT includes a full suite of tools and methods for EXAFS analysis, including functions for pre-edge removal and normalization of EXAFS data, background removal using the AUTOBK method and fitting EXAFS with theoretical calculations for scattering amplitudes and phase shifts from FEFF. The IFEFFIT library is used as the backend to the popular GUI programs ATHENA, ARTEMIS and SIXPACK. LARCH is a successor to IFEFFIT, and includes all the EXAFS functionality of IFEFFIT, while adding functionality for XANES and related X-ray spectroscopies and overcoming several intrinsic limitations of IFEFFIT. For example, LARCH provides better tools for general-purpose data fitting, X-ray fluorescence analysis and interaction with databases of fundamental X-ray data. Written in and extensible with Python, LARCH can make use of the wide range of scientific libraries available for Python.