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Schema helper

JSON to OpenAPI schema

Generate an OpenAPI component schema from sample JSON in one click.
Objects and arrays are mapped to JSON Schema with required fields, and mixed arrays become oneOf definitions.
Everything runs locally in your browser—no data is sent anywhere.

Guide: How to use & features

  • Paste JSON into the input and hit “Convert to OpenAPI.”
  • Objects expand into JSON Schema with properties plus a required array.
  • Arrays infer the element type; if multiple types appear, the tool outputs oneOf.
  • Use copy or clear to reuse the schema or start fresh.

Samples: Sample input & output

Infer schema from a profile object

Input

{"name":"Jane","email":"jane@example.com","verified":true}

Output

{
  "type": "object",
  "properties": {
    "name": {"type": "string"},
    "email": {"type": "string", "format": "email"},
    "verified": {"type": "boolean"}
  },
  "required": ["name", "email", "verified"]
}

FAQ: Frequently asked questions

  • What does the output look like?

    The tool builds components.schemas.Root as JSON Schema with properties and required fields.

  • How are mixed arrays or nulls handled?

    Each element is inferred; if multiple types appear, the array uses oneOf items. Nulls become nullable: true.

  • Is any data sent to a server?

    No. Everything runs locally in your browser with no network requests.

Use cases: Common use cases

  • Drafting schemas

    Transform JSON samples into OpenAPI schema stubs to seed documentation or mock generation.

  • Sharing endpoint expectations fast

    Convert request/response examples and paste them into PRs or issues to align on contract details.

  • Checking consistency with existing specs

    Compare generated stubs with current definitions to spot fields that need updates.

Notes: Notes & limitations

  • Work stays in your browser

    Inputs and outputs remain local. Closing the tab or clearing cache will remove any temporary state.

  • Validate critical data

    Results are helper outputs—double-check them before sending to production systems or sharing externally.

  • Large payloads depend on your device

    Very large text or files can feel slow in some browsers. Use a desktop environment for heavy workloads.

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