Data converter · runs 100% in your browser
Protobuf to JSON Converter
Decode a serialised Protobuf binary message into human-readable JSON, in your browser. Drop your .proto schema and the binary payload — pick the root message type, get JSON out. Useful for inspecting gRPC traffic or debugging serialized API payloads.
How to use
- Drop your .proto schema file.
- Drop the binary protobuf message (.bin / .pb).
- Pick which message type the binary represents.
- Click Convert. The decoded JSON is offered for download.
FAQ
Why do you need the .proto file?
Protobuf binaries don't include schema info — fields are identified by tag numbers, not names. Without the .proto, decoded output would just be {1: ..., 2: ...} with no meaning.
Are nested messages handled?
Yes. protobufjs walks the schema graph and decodes nested messages, repeated fields, oneofs, and maps recursively.
Does my schema or message upload to a server?
No. Conversion runs entirely in your browser using WebAssembly and Web APIs. Open the Network tab in DevTools while you convert — you'll see no outbound traffic carrying your file.
Is this really free?
Yes. No signup, no quota, no upgrade tier. The conversion runs on your machine, so it costs us nothing to host.