EMPEROR (Exoplanet MCMC Parallel tEmpering for RV Orbit Retrieval) searches for planetary signals in radial‑velocity time series and can jointly model data from Astrometry (ascl:1208.001). It applies Bayesian inference with parallel‑tempering MCMC and related posterior samplers (including Adaptive Parallel Tempering MCMC and Dynamic Nested Sampling), various noise models, and convergence tests to explore highly multi‑modal posteriors efficiently. EMPEROR analyzes multi‑instrument, multi‑planet data sets and performs model comparison automatically to identify the model that best describes the data.