Convert Protobuf to JSON

Convert Protobuf to JSON turns basic .proto message definitions into sample JSON objects. The Convert Protobuf to JSON tool runs in-browser, updating instantly with file import, copy, and export support.

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Supported file types: .proto, .txt
Total characters: 0

How to Use:

Start by pasting a .proto message definition into the Input .proto box. For example:

message Person {
  string name = 1;
  int32 age = 2;
  bool subscribed = 3;
}

You can also click Choose File to import a .proto or .txt file containing your Protobuf message. Once added, Convert Protobuf to JSON will extract each field name and type, then generate a mock JSON object using appropriate default values. Strings become empty strings, numbers default to 0, and booleans default to false.

The converted JSON appears immediately in the JSON Output box. Use Copy Output to copy the result, or Export to File to download the output as a .json file. Use Clear All to reset the tool and start fresh.

What Convert Protobuf to JSON can do:

It scans for basic Protobuf message structures and builds out a JSON representation with placeholder data. This helps when mocking data, setting up API contracts, or generating sample payloads from schema definitions. You get instant results, a character counter to track output size, and live flashing feedback every time your output updates. No build tools or compilers required it all runs in the browser.

Example:

Input:

message User {
  string email = 1;
  int32 age = 2;
  bool verified = 3;
}

Output:

{
  "User": {
    "email": "",
    "age": 0,
    "verified": false
  }
}

Common Use Cases:

Convert Protobuf to JSON is perfect when you need quick sample data from a .proto file. Whether you’re mocking API responses, testing integrations, or creating templates for developers, this tool gives you usable JSON instantly. It’s especially helpful when you’re working without a compiler or full Protobuf runtime but still need structured test input.

Useful Tools & Suggestions:

Once it’s converted, Validate JSON helps make sure everything came through cleanly and nothing broke in translation. And if you want a cleaner view of the result, Prettify JSON makes the new structure way easier to read.

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