Do I need the .proto file?

Yes for named fields. Without a schema, protobuf payloads only carry field numbers and wire types.

Which proto syntax is supported?

proto3 messages with scalars, enums, repeated fields and nested messages.

Is my payload uploaded?

No. Parsing and encoding happen entirely in your browser.

Does it work offline and on mobile?

Yes. Once the page has loaded it keeps working without a network connection, and the layout is responsive so it stays usable on phones and tablets.

Do I need an account or an API key?

No. Every tool on Coders Hub is free to use with no sign-up, no API key and no usage limits.

Protobuf ↔ JSON Converter

Convert between .proto-described binary payloads and JSON.

Support

No Login

No API

.proto schema (optional for decode)

Define messages with scalar, repeated, nested message, and enum fields.

Message to use

JSON input

Protobuf wire bytes

Hex

0a 0c 41 64 61 20 4c 6f 76 65 6c 61 63 65 10 24 1a 04 6d 61 74 68 1a 05 6c 6f 67 69 63 22 0f 0a 06 4c 6f 6e 64 6f 6e 12 05 39 30 32 31 30

Base64

CgxBZGEgTG92ZWxhY2UQJBoEbWF0aBoFbG9naWMiDwoGTG9uZG9uEgU5MDIxMA==

About the Protobuf ↔ JSON Converter

Paste a .proto schema and either a JSON object or a base64/hex encoded protobuf payload, then convert in either direction. Field numbers, wire types, repeated fields and nested messages are resolved from the schema, so you can inspect and craft gRPC payloads without any tooling installed.

Examples

Decode payload

0a03416461

Output

JSON{ "name": "Ada" }

Keyboard shortcuts

Copy the main outputCtrl / ⌘ + Shift + C
Download the resultCtrl / ⌘ + S
Share this toolCtrl / ⌘ + Shift + S
Reset the inputsAlt + R
Open the tool search paletteCtrl / ⌘ + K

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Frequently asked questions

Version 1.0.0 · Updated 2026-08-22 · Runs entirely in your browser