The amount of Android application is having a tremendous increasing trend, exerting pressure over practitioners and researchers around application quality, frequent releases, and quick fixing of bugs. This pressure leads practitioners to make usage of automated approaches based on using source-code as input. Nevertheless, third-party services are not able to use these approaches due to privacy factors. In this paper we present MutAPK, an open source mutation testing tool that enables the usage of APK as input for this task. MutAPK generates mutants without the need of having access to source code, because the mutations are done in an intermediate representation of the code (i.e., SMALI) that does not require compilation. MutAPK is publicly available at GitHub: https://bit.ly/2KYvgP9 VIDEO: https://bit.ly/2WOjiyy.