Struct vs protobuf

Both struct and protobuf topics carry binary payloads over NetworkTables. Choose based on interoperability and schema needs.

Struct

• Fixed-size binary layout used by WPILib Java/C++ struct topics
• Best for standard geometry types (Pose2d, Translation2d, …) that already exist on the robot
• Use getStructTopic / useStructTopic with a built-in descriptor or a custom typeName + schema string
• Interoperates directly with WPILib struct publishers/subscribers

Protobuf

• Schema-driven messages via Protocol Buffers
• Best for custom message types defined in .proto files
• Use getProtobufTopic / useProtobufTopic with Zod validators and, when publishing, protoFilePath (Node), protoSource, or messageType
• Schema is exchanged over NetworkTables; decoding can be validated at runtime with Zod

Which to pick

• Matching WPILib geometry / existing struct topics → struct
• Custom app-defined messages with a .proto → protobuf

See the struct and protobuf guides for code examples.