Protobuf and gRPC API Review

Review .proto and related gRPC changes as long-lived contracts. Distinguish what the wire format permits from what generated clients, JSON users, stored data, and mixed-version deployments can safely tolerate.

Start With the Compatibility Envelope

Before deciding whether a change is safe, determine:

• the old and new schema, not only the final file
• whether payloads use binary protobuf, ProtoJSON, text format, or more than one encoding
• whether messages persist in databases, queues, logs, caches, or events
• whether clients exist outside the repository or release independently
• the protobuf syntax or edition and the generated languages/runtime versions
• whether HTTP/JSON transcoding, reflection, service config, or schema registries expose the contract
• the deployment order, rollback window, and duration of mixed-version operation

If context is missing, state the assumption and lower confidence. Do not call a change backward-compatible from the new schema alone.

Review Workflow