Generate JSON Schema from sample JSON

Infer a first-pass JSON Schema from a sample document, including common string formats.

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ToolJSON Schema Generator

Input

Output

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How it works

The sample is parsed and visited recursively: strings get simple date, email, URI, UUID, or IPv4 hints; numbers become integer or number; objects become properties; and arrays infer one item schema or oneOf alternatives. Draft metadata and optional required lists are then added to the formatted document.

Draft 7 is the widely supported starting dialect.
Required properties are enabled to describe the supplied sample completely.

Worked example

Generate from Object

Infer a JSON Schema from a sample user object with format detection

Input

											{
  "name": "Alice",
  "email": "[email protected]",
  "age": 30,
  "active": true
}

Output

												{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "type": "object",
  "properties": {
    "name": {
      "type": "string"
    },
    "email": {
      "type": "string",
      "format": "email"
    },
    "age": {
      "type": "integer"
    },
    "active": {
      "type": "boolean"
    }
  },
  "required": [
    "name",
    "email",
    "age",
    "active"
  ]
}

When to use this

API payloads, form generators, and fixture contract tests use inferred schemas as a starting point.

Edge cases

Mixed primitive arrays become oneOf alternatives instead of one forced type.
A nullable property is omitted from the required list.
A sample cannot reveal bounds, lengths, or cross-field constraints.

References

JSON Schema specification