OpenAPI Validator
Check a local Swagger 2.0, OpenAPI 3.0 or OpenAPI 3.1 document for schema errors and broken internal references. Read the reported paths without querying your API.
Open toolJSON to Protobuf Converter
Draft proto3 messages from a JSON sample. Review inferred scalar types, nested messages and numbered fields before adopting the schema in a protocol.
Free to useNo sign-upRuns in your browser
Enter your details
Enter the inputs, then select Generate Protobuf.
Your result
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Result will appear here
How JSON to Protobuf Converter works
Infer scalar, array and nested object fields with a bounded structural mapper and render proto3 messages.
Processing uses bundled libraries in this browser. The download contains the generated source or document, rather than a link to a conversion service.
How to generate Protobuf
Start with the supported input, then check the generated result.
Enter the source details
Use JSON sample, Root type name. The form starts with an example you can replace.
Input and settings
Tool result
Review and save the output
Review a proto3 message schema inferred from JSON. Download the generated file and check it in the application where you plan to use it.
Review the details
When to use JSON to Protobuf Converter
These workflows use the formats and behavior supported by this implementation.
Draft a new message schema
Use a representative JSON object to sketch a new proto3 message. Mixed field types and empty or null-only examples cannot establish a usable type.
Review nested message fields
Objects become messages and arrays become repeated fields. Review inferred numbers and normalized names before integrating the schema.
Plan stable field numbering
Field numbers are assigned from the sample order. Once a protocol is in use, maintain stable numbers and review every subsequent schema change.
What the output contains
Keep the output format and conversion policy in view.
A proto3 message schema inferred from JSON. Infer scalar, array and nested object fields with a bounded structural mapper and render proto3 messages.
Compare the result with the original before replacing a source file. Conversion limits are listed below.
Supported input and limits
Check these conditions before relying on the result.
Mixed-type fields, null-only fields and nested arrays are rejected. Sample-derived field numbers are not a migration policy. Review integer ranges, optional values and stable numbering before using a schema in an existing protocol. No compiler is run.
Input and results are not stored after leaving or reloading. Keep the original and download any output you need.
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Generate the supported output, review it, and save a copy for your next step.
JSON to Protobuf Converter: common questions
Answers about using JSON to Protobuf Converter and understanding its results.
What does this tool produce?
It produces a proto3 message schema inferred from JSON. Mixed-type fields, null-only fields and nested arrays are rejected. Sample-derived field numbers are not a migration policy. Review integer ranges, optional values and stable numbering before using a schema in an existing protocol. No compiler is run.
Is my input uploaded?
Processing runs in this browser with local bundled libraries. No input is sent to a conversion server. Download your result before leaving the page.