As mobile devices continue to dominate internet usage, optimizing client-server interactions becomes increasingly important for both users and developers. In this talk, we will explore the benefits of using Protocol Buffers (Protobuf) in mobile applications, compared to traditional RESTful APIs. Protobuf is a binary serialization format designed for machine-to-machine communication, which can significantly reduce the size of payloads exchanged between the client and server. We will discuss how to implement Protobuf in Android applications, including a basic implementation example. Additionally, we will review some benchmarks that demonstrate the efficiency of Protobuf usage and how it can improve mobile application performance. Finally, we will also discuss some common pain points and personal learnings when implementing Protobuf in a production project. Attendees will leave with a solid understanding of Protobuf and how to leverage it to optimize their Android applications.