prost

Prost is an open-source Rust library for Protocol Buffers. It provides a fast, ergonomic implementation of Protocol Buffers and a code generation workflow that converts .proto files into Rust types. Prost focuses on Proto3 features and does not implement Proto2 features such as required fields.

Prost centers on generated message types with methods for encoding, decoding, and length calculation. The runtime is designed to be lightweight and memory efficient, using the bytes crate for buffer management. Code generation is performed by the prost-build crate, which is run from a build script and produces Rust types alongside implementations of the prost::Message trait.

Well-known protobuf types, such as Timestamp and Duration, are provided in a separate prost-types crate, simplifying reuse of common definitions. Prost is widely used in the Rust ecosystem, particularly with gRPC frameworks like Tonic, which relies on Prost to generate service messages and data structures from .proto files.

Prost is an actively developed, open-source project with contributions and documentation from the community. It emphasizes safety, performance, and compatibility with standard Protocol Buffers definitions, making it a common choice for Rust projects that exchange data using protobufs.