Protobuf Decoder — No Schema Needed

How to use

1. Paste Base64 or hex bytes into the input area, or click "Open file" to load a raw .pb binary. Drag-and-drop also works on the input area.
2. Select the format (Auto-detect works for most cases) then click "Decode". Gzip-compressed messages decompress automatically.
3. Inspect the decoded field tree — each row shows the field number, wire type, raw value, and interpretations such as UTF-8 string, sint64 (zigzag), float32, or float64. Click "Copy as JSON" to export the structure.

Decode variants

• Decode from Base64
• Decode from Hex bytes
• Decode gzip-compressed protobuf
• Decode gRPC message body
• Inspect nested messages

Related tools

• JSON Schema Validator
• YAML Validator
• XML Formatter
• JSON Formatter

Preguntas frecuentes

Does my data leave my device?

No. All decoding runs entirely in your browser — nothing is sent to any server. You can use this tool offline after the first page load.

Do I need a .proto file or schema to decode?

No. The decoder works directly on the wire format. It recovers field numbers, wire types, and raw values without a schema. The only thing you lose without a .proto file is the human-readable field names.

What input formats are supported?

Base64-encoded bytes (the most common format from gRPC traces and API debuggers), hex bytes with or without spaces, and raw binary .pb files dragged onto the drop zone. Gzip-compressed messages are decompressed automatically.

How does nested message detection work?

Every length-delimited field is speculatively parsed as a protobuf message. If the bytes parse cleanly as valid field tags and wire types all the way through, the field is shown as an expandable nested subtree. Otherwise the bytes are shown as a UTF-8 string (if decodable) or raw hex.

What browsers are supported?

Chrome 80+, Firefox 113+, Safari 16.4+, and Edge 80+. The tool relies on BigInt, TextDecoder, and DecompressionStream — all standard APIs, no WebAssembly or third-party libraries required.