Infers a proto3 message from a JSON sample.
JSON to Protobuf infers a proto3 message definition from a JSON sample, so you can turn an example payload into a starting .proto schema without writing it by hand. It walks the JSON object, maps each field to a scalar or nested message type, and outputs a syntax = "proto3" definition with sequential field numbers. It's useful when you're moving an existing JSON API toward gRPC or Protocol Buffers and want a quick first draft of the message structure.
No. The conversion runs entirely in your browser and nothing is uploaded. Your JSON never leaves your device.
It always emits proto3, prefixing the output with syntax = "proto3";. Field numbers are assigned sequentially starting from 1 in the order the JSON keys appear.
Booleans become bool, strings become string, integers become int64, and other numbers become double. Nested objects become their own message types, and arrays become repeated fields based on their first element.
Null values are typed as string, since the real type can't be inferred. An empty array is treated as a repeated string field because there's no element to inspect.
Yes. The top-level input must be a JSON object; a bare array, primitive, or null is rejected. Invalid JSON also produces an error message.