Beyond protoc --decode: Schema Inference, Lossless Decoding, and... Frederic Ruget, S3NS

Don't miss out! Join us at our next KubeCon + CloudNativeCon event in Salt Lake City, United States (Nov 9–12, 2026). Connect with our current graduated, incubating, and sandbox projects as the community gathers to further the education and advancement of cloud native computing. Learn more at https://kubecon.io Beyond protoc --decode: Schema Inference, Lossless Decoding, and Descriptor Archaeology - Frederic Ruget, S3NS (Thales × Google Cloud) Every gRPC engineer eventually faces a binary .pb blob of unknown type, a compiled descriptor with no .proto source, or an editions descriptor a downstream toolchain cannot consume. Standard tooling stops short: protoc --decode requires the original descriptor and exact type name, silently discards non-canonical bytes, crashes on malformed input. prototools is a pair of open-source CLI tools that fill this gap. prototext decodes binary protobuf with or without a schema. Given a descriptor DB, it automatically infers the message type — ranking all candidates from a corpus of thousands of types in seconds. It also preserves every non-canonical byte via inline annotations and round-trips byte-exact, even for malformed protobufs. reproto reconstructs compilable .proto source files from any FileDescriptorSet, handling proto2, proto3, and editions. It also builds the indexed descriptor databases that power prototext's auto-inference. The talk is built around a live terminal demo.