Protobuf to OpenAPI Converter
Convert Protocol Buffers (Proto3 & Proto2) messages and gRPC services into OpenAPI 3.0 specifications in your browser.
At a glance
Protobuf to OpenAPI Converter transforms Protocol Buffers (Proto3 and Proto2) messages and gRPC services into OpenAPI 3.0 and 3.1 specifications. It maps scalar types, repeated arrays, maps, and enums into components.schemas, and translates RPC definitions into OpenAPI paths in browser memory.
100% Client-Side In-Browser Protobuf to OpenAPI Converter
Compile Protocol Buffers (Proto2 and Proto3) messages, enums, and gRPC services directly into OpenAPI 3.0 / 3.1 specifications entirely in browser memory.
Why Use This Protobuf to OpenAPI Converter?
How to Use Protobuf to OpenAPI Converter
Paste Protobuf Definition
Enter or paste your syntax = 'proto3' message, enum, and service definitions into the editor.
Configure OpenAPI Options
Select OpenAPI 3.0 or 3.1, customize your API title, and choose whether to generate paths from gRPC services.
Copy or Download OpenAPI
Inspect the generated OpenAPI JSON specification, copy it to your clipboard, or export as a .json file.
Protocol Buffers to OpenAPI 3.0 Specification
Transpiles User and GetUserRequest protobuf messages into components.schemas and generates a POST /UserService/GetUser endpoint.
syntax = "proto3";
package api;
message User {
int64 id = 1;
string name = 2;
}
message GetUserRequest {
int64 id = 1;
}
service UserService {
rpc GetUser (GetUserRequest) returns (User);
}
{
"openapi": "3.0.0",
"info": {
"title": "api API",
"version": "1.0.0"
},
"paths": {
"/UserService/GetUser": {
"post": {
"operationId": "UserService_GetUser",
"responses": { "200": { "content": { "application/json": { "schema": { "$ref": "#/components/schemas/User" } } } } }
}
}
},
"components": {
"schemas": {
"User": {
"type": "object",
"properties": { "id": { "type": "integer", "format": "int64" }, "name": { "type": "string" } }
}
}
}
}
Technical Specifications & Engine Details
| Specification | Details |
|---|---|
| Supported Formats | TEXT/PLAIN, APPLICATION/X-PROTOBUF, .PROTO → APPLICATION/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 an external server?
Does it support nested messages and enums?
How does it convert gRPC service definitions?
Can I choose between OpenAPI 3.0 and 3.1?
Methodology
This tool runs entirely in your browser. The example above shows a representative input and the result it produces.
Last updated .