Decode Protobuf from Base64
Paste Base64-encoded Protocol Buffer bytes to inspect field numbers, wire types, varint values, and nested messages — all in your browser without uploading anything.
Base64 is the most common encoding for Protocol Buffer bytes when they appear in logs, API traces, gRPC debug output, or developer tools. Every gRPC request body is a 5-byte framing header followed by a protobuf message; the message bytes are often Base64-encoded when captured via proxies or browser DevTools.
The Protobuf Decoder accepts standard Base64
(RFC 4648) with or without padding (=) and with or without whitespace. It automatically
detects Base64 input when you select Auto-detect format, or you can force it with
the Base64 option.
How to decode a Base64 protobuf message
-
Copy the Base64 string from your log, DevTools network panel, or API trace. A typical protobuf
encoded as Base64 looks like
CgZoZWxsbw==or longer strings without padding. - Open the Protobuf Decoder and paste the Base64 string into the input area. Select Base64 as the format or leave it on Auto-detect.
- Click Decode. The tool shows each field number, wire type, and value. String fields appear as UTF-8 text; nested messages are shown as expandable subtrees. Use Copy as JSON to export the decoded structure.