OpenAPI to JSON Schema Converter
Convert OpenAPI 3.0, 3.1, and Swagger specifications into standard JSON Schema Draft-07 and Draft 2020-12 in your browser.
At a glance
OpenAPI to JSON Schema Converter extracts and transforms OpenAPI 3.0 and 3.1 schemas into standard JSON Schema Draft-07 or Draft 2020-12. It rewrites components.schemas references into definitions or $defs, converts nullable properties into standard union types, preserves validation constraints, and exports clean JSON or YAML.
100% Client-Side OpenAPI to JSON Schema Transpiler
Draft-07 & Draft 2020-12Extract and transpile OpenAPI 3.0, 3.1, and Swagger 2.0 specs into standard JSON Schema. Automatic reference rewriting, nullable union translation, and YAML/JSON export running entirely in browser memory.
OpenAPI stores data definitions inside #/components/schemas/<Name> (OpenAPI 3) or #/definitions/<Name> (Swagger 2). The engine rewrites internal pointers into #/definitions/<Name> for Draft-07 or #/$defs/<Name> for Draft 2020-12.
OpenAPI 3.0 uses nullable: true, which is not valid JSON Schema. The engine automatically translates nullable properties into standard union type arrays type: ["string", "null"] or wraps complex reference pointers in anyOf.
Enterprise API specifications containing private schemas and endpoint architecture never leave your local machine memory. Zero server round-trips, zero telemetry tracking, and zero marginal cost.
Why Use This OpenAPI to JSON Schema Converter?
How to Use OpenAPI to JSON Schema Converter
Paste OpenAPI or Swagger Specification
Enter or paste your OpenAPI 3.0, 3.1, or Swagger 2.0 document in YAML or JSON format into the editor.
Select Target Dialect & Format
Choose between JSON Schema Draft-07 and Draft 2020-12, select your output format (JSON or YAML), and select schema extraction mode.
Copy or Download Schema
Copy the compiled standard JSON Schema directly to your clipboard or download it to your workspace.
OpenAPI 3.0 to JSON Schema Draft-07 Conversion
Demonstrates converting an OpenAPI 3.0 schema with nullable properties into standard JSON Schema Draft-07 with nullable translated to a type union array.
openapi: 3.0.3
info:
title: User API
version: 1.0.0
components:
schemas:
User:
type: object
required: [id, name]
properties:
id: { type: integer }
name: { type: string }
bio: { type: string, nullable: true }
{
"$schema": "http://json-schema.org/draft-07/schema#",
"title": "User",
"type": "object",
"required": ["id", "name"],
"properties": {
"id": { "type": "integer" },
"name": { "type": "string" },
"bio": { "type": ["string", "null"] }
}
}
Technical Specifications & Engine Details
| Specification | Details |
|---|---|
| Supported Formats | YAML, JSON, OPENAPI → JSON, YAML, JSON-SCHEMA |
| Execution Mode | 100% Client-Side In-Browser (client) |
| Browser Requirements | Modern web browser with JavaScript enabled. |
| Performance Constraints | Zero external dependencies. Runs 100% client-side in browser memory. |
100% Client-Side Privacy Guarantee
Your files and data remain strictly on your local device. Computations run locally using browser memory with zero network uploads.
Frequently Asked Questions
How does this tool handle OpenAPI components.schemas references?
What happens to OpenAPI 3.0 nullable fields?
Can I convert Swagger 2.0 documents?
Is my API specification kept private?
Methodology
This tool runs entirely in your browser. The example above shows a representative input and the result it produces.
Last updated .