OpenAPI to JSON Schema Converter — Free Online

Extract OpenAPI 3.0–3.2 components.schemas into JSON Schema — default Draft 2020-12 ($defs), optional Draft-07 (definitions). Browser-local, no upload.

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OpenAPI to JSON Schema documentation
Extract OpenAPI components.schemas into JSON Schema (2020-12 or Draft-07).

Developer notes

OpenAPI 3.0 schemas convert via @openapi-contrib/openapi-schema-to-json-schema. OpenAPI 3.1 / 3.2 use a best-effort strip of OAS-only keywords. Default output: $schema 2020-12 + $defs; optional Draft-07 remap ($schema + definitions + #/definitions refs). Live convert on paste/sample; explicit Convert (⌘↵) for manual edits; Monaco JSON/YAML input + Shiki JSON output. Empty components.schemas → error. External $ref rejected. Max input 512 KiB.

Options

Target draft
2020-12 (default) emits $schema + $defs. Draft-07 remaps to the Draft-07 $schema URI, definitions instead of $defs, and #/definitions/… refs — a structural rename only; 2020-12-only keywords are not rewritten.

Use cases

Reuse OpenAPI models as standalone JSON Schema. Feed extracted schemas into JSON Schema Validator. Diff schema shapes outside of a full OpenAPI document.

Examples

OpenAPI YAML → JSON Schema $defs

Before

openapi: "3.0.3" info: title: Pets version: 1.0.0 paths: {} components: schemas: Foo: type: object properties: id: type: string Bar: type: object properties: name: type: string

After

{ "$schema": "https://json-schema.org/draft/2020-12/schema", "$defs": { "Foo": { ... }, "Bar": { ... } } }

Empty schemas rejected

Before

openapi: "3.0.3" info: title: t version: "1" paths: {} components: schemas: {}

After

Error: empty components.schemas

OpenAPI to JSON Schema FAQ

Common questions

Is 3.1 conversion identical to Draft-07?

No. OpenAPI 3.1/3.2 conversion is a best-effort keyword strip. Default output is Draft 2020-12 ($defs). Choose Draft-07 for a structural remap (definitions + Draft-07 $schema) — not a full keyword rewrite. See Options.

What if there is no Root schema?

All schemas land under $defs (or definitions when Draft-07 is selected) with no invented root type/properties. A schema named Root also gets a top-level $ref to that entry.

Related tools?

Convert the other way with JSON Schema to OpenAPI, or validate the OpenAPI source with Validate OpenAPI.

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