JSON to Protobuf Converter
Infer a proto3 schema (.proto) from a JSON sample — fields, types, and nested messages.
Types are inferred from values: string, int32/double, bool, nested objects become nested messages, and arrays become repeated fields. Field names are snake_cased and numbered. Null or empty arrays produce a best-effort guess with a warning — review and tighten the schema before shipping.
About this tool
Turn a JSON sample into a proto3 schema: scalar types, nested messages, and repeated fields, snake_cased and numbered. Free and client-side. JSON to Protobuf Converter runs in the browser on DevTools. There is no signup, and your input stays on this device unless the tool explicitly performs a live network lookup.
What this tool does not do
- JSON to Protobuf Converter is a free in-browser utility, not a hosted API. It does not keep server-side history and is not a substitute for production verification in your own stack.
How do I use this tool?
How do I use JSON to Protobuf Converter?
Open JSON to Protobuf Converter, enter or paste your input, and copy the result. The page works without an account.
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