JSON to Protobuf Converter

Generate Protocol Buffer .proto schema definitions from JSON data with intelligent type inference.

Message Package Syntax Naming Comments

JSON Input

Protobuf Output

2 messages

syntax = "proto3";
message Root {
  // e.g. 1
  int32 user_id = 1;
  // e.g. "Alice"
  string user_name = 2;
  // e.g. "alice@example.com"
  string email = 3;
  // e.g. true
  bool is_active = 4;
  // e.g. 95.5
  double score = 5;
  // e.g. ["admin","verified"]
  repeated string tags = 6;
  // e.g. {"bio":"Software engineer","avatarU
  Profile profile = 7;
}

message Profile {
  // e.g. "Software engineer"
  string bio = 1;
  // e.g. "https://example.com/avatar.png"
  string avatar_url = 2;
}

How to Use

Paste JSON or upload a .json file.
Set message name, package, syntax version, and naming convention.
Copy or download the generated .proto file.

Frequently Asked Questions

How does JSON to Protobuf conversion work?

The tool analyzes your JSON structure and data types, then generates matching Protocol Buffer message definitions with proper field types and sequential numbering.

Does it support proto2 and proto3?

Yes. Choose between proto3 (default, recommended for new projects) and proto2 syntax. Proto2 adds the optional keyword to fields.

How are nested objects handled?

Nested JSON objects become nested Protobuf message types. Arrays become repeated fields with the appropriate element type.

Is my data secure?

Yes. All processing happens in your browser. No data is uploaded to any server.

Can I customize field naming?

Yes. Choose between snake_case (Protobuf convention) and camelCase for field names. You can also set custom message and package names.