The article introduces Tracer 1.7, a software package designed for visualizing and analyzing MCMC trace files generated from Bayesian phylogenetic inference. Tracer is essential for understanding the posterior distribution of model parameters, which is crucial in Bayesian phylogenetics. It offers features such as kernel density estimation, multivariate visualization, demographic trajectory reconstruction, and conditional posterior distribution summary. Tracer is compatible with output from various MCMC programs, including BEAST, BEAST2, LAMARC, Migrate, MrBayes, and RevBayes. The software provides statistical summaries and visualizations for continuous, integer, and categorical parameters, aiding in the assessment of MCMC mixing and convergence. An example using Tracer to infer the spatial dispersal and cross-species dynamics of rabies virus in North American bats is provided, demonstrating its utility in phylogeographic and demographic analyses. Tracer is open-source and available at http://beast.community/tracer, with tutorials and support for users.The article introduces Tracer 1.7, a software package designed for visualizing and analyzing MCMC trace files generated from Bayesian phylogenetic inference. Tracer is essential for understanding the posterior distribution of model parameters, which is crucial in Bayesian phylogenetics. It offers features such as kernel density estimation, multivariate visualization, demographic trajectory reconstruction, and conditional posterior distribution summary. Tracer is compatible with output from various MCMC programs, including BEAST, BEAST2, LAMARC, Migrate, MrBayes, and RevBayes. The software provides statistical summaries and visualizations for continuous, integer, and categorical parameters, aiding in the assessment of MCMC mixing and convergence. An example using Tracer to infer the spatial dispersal and cross-species dynamics of rabies virus in North American bats is provided, demonstrating its utility in phylogeographic and demographic analyses. Tracer is open-source and available at http://beast.community/tracer, with tutorials and support for users.