Applies the Beta regression model in the Bayesian statistical view with the possibility of adding a spatial effect in the parameters, the Beta regression is used when the response variable is a proportion variable, that is, it only accepts values between 0 and 1. The package 'bayesbr' uses 'rstan' package to build the Bayesian statistical models. The main function of the package receives as a parameter a form informing the independent variable and the co-variables of the model to be made, as output it returns a list with the results of the model. For more details see Ferrari and Cribari-Neto (2004) <doi:10.1080/0266476042000214501> and Hoffman and Gelman (2014) <arXiv:1111.4246>.