Protobuf to JSON Schema Converter
Convert Protocol Buffers (Proto3 & Proto2) message contracts into standardized JSON Schema specifications in your browser.
At a glance
Protobuf to JSON Schema Converter transforms Protocol Buffers (Proto3 and Proto2) messages into valid JSON Schema (Draft-07 and 2020-12) documents. It accurately maps scalar types, repeated arrays, maps, enums, oneof blocks, and internal references into compliant $defs schemas in browser memory.
100% Client-Side In-Browser Protobuf to JSON Schema Converter
Compile Protocol Buffers v2 and v3 (.proto) message contracts directly into JSON Schema (Draft-07 & 2020-12) specifications in your browser memory.
Generation Options
int32 → integer (int32), int64 → integer (int64), repeated → array, map<string, T> → additionalProperties, and oneof → oneOf.
Why Use This Protobuf to JSON Schema Converter?
How to Use Protobuf to JSON Schema Converter
Paste Protocol Buffers Definition
Enter or paste your .proto file contents into the Protobuf definition editor.
Configure Schema Options
Select target JSON Schema draft (2020-12 or Draft-07) and select the root message if multiple messages exist.
Copy or Export JSON Schema
Review the generated JSON Schema specification, copy it to your clipboard, or download it as a .json schema file.
Protobuf to JSON Schema Output
Converts Proto3 User contract into a valid Draft 2020-12 JSON Schema specification with precise integer formats, typed array items, and required properties array.
syntax = "proto3";
message User {
int64 id = 1;
string username = 2;
string email = 3;
repeated string roles = 4;
}
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"title": "User",
"type": "object",
"properties": {
"id": {
"type": "integer",
"format": "int64"
},
"username": {
"type": "string"
},
"email": {
"type": "string"
},
"roles": {
"type": "array",
"items": {
"type": "string"
}
}
},
"required": [
"id",
"username",
"email",
"roles"
]
}
Technical Specifications & Engine Details
| Specification | Details |
|---|---|
| Supported Formats | TEXT/PLAIN, APPLICATION/X-PROTOBUF, .PROTO → APPLICATION/JSON, APPLICATION/SCHEMA+JSON, TEXT/PLAIN, .JSON |
| Execution Mode | 100% Client-Side In-Browser (client) |
| Browser Requirements | Modern browser with JavaScript enabled. |
| Performance Constraints | Runs client-side in browser memory. Performance and file limits are bounded by available local device RAM. |
100% Client-Side Privacy Guarantee
Your files remain strictly on your local device. Zero data is transmitted to external servers.
Frequently Asked Questions
Are my Protobuf definitions uploaded to any server?
Which JSON Schema drafts are supported?
How does the tool handle Protobuf oneof unions?
Can I convert .proto files containing multiple messages?
Methodology
This tool runs entirely in your browser. The example above shows a representative input and the result it produces.
Last updated .