JSON to Protobuf Converter
ConvertersGenerate a proto3 message definition from a JSON object instantly in your browser. Type-inferred scalar fields and nested messages. One-way. 100% client-side.
JSON →
Protobuf
JSONjson
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Protobufplaintext
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Input: 315 chars
About JSON to Protobuf Converter
The JSON to proto3 converter generates a Protocol Buffer 3 (proto3) message definition from a JSON sample. Strings map to `string`, integers to `int32`, floats to `double`, booleans to `bool`, nested objects to nested `message` types, and arrays to `repeated` fields. The output includes `syntax = "proto3"` and is ready for use with `protoc`.
Features
- ✓Custom JSON-to-proto3 schema inference engine
- ✓Generates proto3 message definitions with correct field types
- ✓string → string, integer → int32, float → double, boolean → bool
- ✓Nested objects → nested message types
- ✓Arrays → repeated field modifier
- ✓Field numbers assigned sequentially
- ✓Includes syntax = "proto3" header
- ✓Download generated proto file as a .proto file
- ✓Copy output to clipboard in one click
- ✓Web Worker processing — never blocks the UI
- ✓100% client-side — data never leaves your browser
Common Use Cases
- Scaffolding a Protobuf schema from a JSON API response for gRPC migration
- Generating proto3 message definitions for new microservice schemas
- Quickly prototyping Protobuf schemas from JSON sample data
- Converting JSON payloads to Protobuf definitions for streaming pipelines
Frequently Asked Questions
QIs the output compatible with protoc?
Yes — the generated proto3 syntax is compatible with protoc and gRPC toolchains.
QAre proto3 well-known types used?
No — the output uses native proto3 scalar types. Adding google.protobuf.Timestamp or other well-known types requires manual editing.
QIs my data sent to a server?
No. All schema generation runs in a Web Worker inside your browser.