Bayesian X-ray Analysis (BXA) allows reliable parameter inference and model comparison in X-ray astronomy. BXA connects the nested sampling algorithms MultiNest and UltraNest to the X-ray spectral analysis environments Xspec (https://heasarc.gsfc.nasa.gov/xanadu/xspec/) and Sherpa (http://cxc.cfa.harvard.edu/sherpa/). This allows reliable and automatic Bayesian parameter estimation and model comparison.