Protobuf Text ↔ JSON Converter
Convert Protocol Buffers text format (prototext) to JSON and back. Schema-less structural conversion: nested messages become objects and repeated fields become arrays. Pick a direction and indentation.
Input
Output
More ways to use this tool
REST API
curl -X POST https://api.iotools.cloud/v1/tool/protobuf-text-json-converter \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"inputText": "# Person message example\nname: \"John Doe\"\nid: 12…",
"convertMode": "proto-to-json",
"indentation": "2"
}'Swap in your own key from your account. The tool's fields are the body — no wrapper.
Ask an AI agent
Use the IOTools `protobuf-text-json-converter` tool (Protobuf Text ↔ JSON Converter) on this input:
YOUR_INPUT_HEREPaste this at any agent connected to the IOTools MCP server, then add your input.
Embed widget
<iframe
src="https://iotools.cloud/embed/protobuf-text-json-converter/"
width="100%" height="520" frameborder="0" scrolling="no" loading="lazy"
title="Protobuf Text ↔ JSON Converter — iotools.cloud"
sandbox="allow-scripts allow-forms allow-same-origin allow-downloads allow-popups allow-popups-to-escape-sandbox"
allow="clipboard-write"
style="width:100%;border:1px solid #e5e7eb;border-radius:12px;overflow:hidden"></iframe>
<script src="https://iotools.cloud/embed.js" async></script>Drop this into your own page — free, no key required, just a link back.
| Cost per API/MCP call | From 5 credits |
|---|---|
| Need more credits? | View pricing |
Also available with
Guides
Convert Protocol Buffers text format (also called prototext or textproto) to JSON and back, right in your browser. Paste a message, pick a direction, and get a clean, indented result — no .proto schema, no compiler, no upload.
This is a schema-less, structural converter. It maps the shape of the data, not its wire encoding: it does not decode or produce binary protobuf. If you have the human-readable text form (name: "Alice", nested { } blocks, repeated keys), this tool is for you.
How to use it
- Paste your Protobuf text format or JSON into the Input box.
- Choose a Direction:
- Protobuf Text → JSON turns prototext into a JSON object.
- JSON → Protobuf Text turns a JSON object back into prototext.
- Pick 2 or 4 space indentation for the output.
- The Result updates automatically. Copy or download it.
What gets converted
- Scalars — quoted strings, integers, floats, and
true/falsebooleans. - Nested messages — a
field { ... }block (or the olderfield < ... >form) becomes a nested JSON object. - Repeated fields — a key that appears more than once collapses into a JSON array, and JSON arrays expand back into repeated keys.
- Enum values — bare
UPPER_CASEidentifiers stay unquoted when writing prototext and become plain strings in JSON. - Comments —
#line comments in prototext are ignored while parsing.
Example
Prototext input:
name: "John Doe"
id: 1234
address {
city: "Springfield"
}
tags: "developer"
tags: "golang"Becomes JSON:
{
"name": "John Doe",
"id": 1234,
"address": { "city": "Springfield" },
"tags": ["developer", "golang"]
}Why isn't this the same as binary protobuf?
Binary protobuf encoding requires a .proto schema so it knows each field's number and type. Text format is self-describing enough to read structurally, which is why this converter can work without a schema. Use it for debugging log dumps, fixtures, and config in text format — not for parsing .pb binary payloads.
Does my data leave the browser?
No. The conversion runs entirely client-side in your browser. Nothing you paste is sent to a server.