Modern software produces a lot of events that can be analyzed using process mining techniques. The first step in any process mining pipeline is the collection of event logs. Then, those event logs need to be stored persistently on the disk to be transferred via local and global networks. The problem is that software event logs usually consist of many events, each of which can specify tens of attributes. In such a context, the event log stored in the conventional XML-based XES format consumes a tremendous amount of memory. Moreover, it is not read-friendly, i.e., does not provide tools with any advantage while reading an XES file. In this paper, we present bXES, a binary format for storing and transferring event logs, especially software event logs. We highlight main characteristics of software event logs which are utilized in the format scheme, and next we describe the new format. We developed open-source tools to convert XES logs to bXES and vice versa. Tools are available for C# and Rust ecosystems. Finally, we conduct experiments to demonstrate the bXES compatibility and evaluate it. Based on experimental data, bXES event logs are significantly more compact than conventional XES logs and can compete with logs stored in binary EXI format. This reduces storage volume needs and weakens communication constraints when transferring event logs. The experiments are conducted with data from real-life business processes and software events.