OpenAPI to JSON Schema Converter — Free Online

Q: 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.

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

Options

Draft

Output is standalone JSON Schema — validate instance data separately. Use JSON Schema validator to check data against the extracted schema.

Conversion results

Ready

Paste an OpenAPI document — conversion runs on paste/sample or when you click Convert (⌘↵).

OpenAPI document

0chars0 B1lines

JSON Schema

0chars0 B1lines

Conversion runs in your browser — nothing is uploaded.

Share this tool:

Loading…

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.

API & schemas

OpenAPI tools to format, validate, and lint your specs.

Format OpenAPI

Validate OpenAPI

Lint OpenAPI

JSON Schema to OpenAPI

JSON Schema Validator

Validate GraphQL

Explore other tool categories

Minify

Shrink code and assets for production — minify JavaScript, CSS, HTML, JSON and XML before gzip or CDN deploy.

Beautify

Make code readable with consistent indentation — beautify JavaScript, CSS, TypeScript, SCSS, LESS, Markdown, GraphQL, SQL, YAML and more in your browser.

Unminify

Expand minified or compressed code — unminify JavaScript, CSS, TypeScript, SCSS, LESS, SQL, YAML and other formats when debugging or reviewing.

Conversion

Transform data between JSON, YAML, XML and CSV locally — no server uploads.

CSS preprocessors

Compile SCSS or LESS to standard CSS in the browser — pair with beautify or minify for a full stylesheet workflow.

JSON Tools

Validate, format, diff and explore JSON payloads — complementary to minifiers and converters.

SVG Tools

Preview, optimize with SVGO, export Data URI, resize, beautify, convert to JSX and validate SVG — all in your browser.

DevOps & Infra

Terraform HCL format/validate/minify, Dockerfile format & lint, Docker Compose and .env validation.

CI/CD

GitHub Actions and GitLab CI — format YAML and check workflow/job structure in your browser.

Logs & observability

Line-oriented JSON/NDJSON and Nginx/Apache access logs — format, filter, validate, and CSV/TSV.

Kubernetes

Multi-doc manifests, structural validate, Ingress/Deployment starters, and Helm values formatting.

Networking / IP

CIDR, subnets, and IPv4/IPv6 helpers — in your browser.

Security & tokens

JWKS, X.509 certificates, and secrets scan — browser-local.

Encoding

Encode or decode Base64, URL components and HTML entities — client-side only.

Developer utilities

Timestamps, UUID, ULID, Nanoid, cron, passwords, regex, slugify, number bases, case, text diff, and chmod — all client-side.

Text & Markdown

Count words, build Markdown TOCs, and clean line lists — all in your browser.

Serialization

Serialize and deserialize PHP data structures beside JSON workflows.