Safestats is for designing and applying safe hypothesis tests. It can be used for designing hypothesis tests in the prospective or randomised controlled trial (RCT) setting, where the tests can be used under optional stopping and experiments often can be stopped early. The 'pilot' functions in the package also enable using the safe tests in the observational/ retrospective setting. For examples and explanation about which test to choose for which study setup, our vignette can be used (see below). The current version includes safe t-tests and tests of two proportions. The initial paper on the theory of safe testing and a worked-out example for the t-test can be found in 'Grünwald, P.D, de Heide, R, & Koolen-Wijkstra, W.M. (2019). Safe Testing. e-Print archive'.