JSON → OpenAPI draft

Client

Paste example JSON and get a small OpenAPI 3.0 file: one path, one operation, and a schema inferred from your sample—handy for bootstrapping specs next to the JSON Schema tool.

Learn more: OpenAPI from samples

Emit openapi: 3.0.3 with a single path and operation, embedding a JSON Schema inferred from your paste—choose request body (POST/PUT/PATCH/DELETE) or a JSON response (typical for GET).

Not a full generator

Real specs add servers, securitySchemes, parameters, and reusable components. Treat this output as a fragment to merge into your team’s source of truth.

Schema inference

The same draft-07 style inference as the JSON Schema page applies—one example does not prove every future field or discriminated union.

JSON → OpenAPI draft

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Infers a JSON Schema from your sample (same engine as JSON Schema infer) and wraps it in a minimal OpenAPI paths entry—edit names and methods before pasting into a larger spec.

Payload role
Output

Common use cases

  • Draft an operation for internal docs when you only have a real request/response body.
  • Pair with hand-written components and security blocks in your repo’s main openapi.yaml.
  • Switch to “Response” and GET when your sample is a payload shape you return from a read endpoint.

Common mistakes to avoid

  • Treating inference as the full contract

    One sample cannot prove optional fields, unions, or formats—tighten the generated schema before publishing.

FAQ

Is my JSON sent to Toolcore servers?

No. Parsing and OpenAPI assembly run entirely in your browser.

More tools

Related utilities you can open in another tab—mostly client-side.