The BRAT is completely free to use and its source code is publicly available in a GitHub repository. In order to download the installers for the software, we ask people to register to the site. This is done simply to keep track of how many people are using the tool and it is only required to provide an email (your email will be used only to send our newsletter and will not be shared with other entities or used for any other purpose). The registration needs to be done only once, and the user created will give you access to future releases of the software and also to the forums in this site. If for any reason you do not wish to provide an email and create a user, there is the possibility to download the source code from GitHub and compile the tool. However please note that compilation of the tool is not trivial and it is only advised to people with experience in compiling complex software.