BLE <3 Protobuf: Designing Schemas for the Smallest Packets in the Room

Protocol buffers (protobuf) is a serialization format widely used in client-server communication. Compared to JSON, it produces a more compact wire format, which matters when every byte counts. This makes it a strong fit for Bluetooth Low Energy (BLE) communication, where maximum packet sizes are measured in the hundreds of bytes, or fewer.

This talk dives into the best practices for using protobuf over BLE, drawn from a real app. We'll cover how to design protobuf messages that work across a wide range of MTU sizes (down to the minimum of 23 bytes), strategies for fragmenting and reassembling messages that exceed a single MTU, and how to account for the overhead encryption adds to your payload budget.

Attendees will leave with a practical understanding of sizing protobuf schemas against BLE constraints, plus patterns for fragmentation and reassembly they can apply directly to their own mobile and embedded projects.