Required keys
Keys present in every example are listed in required; others stay optional.
JSON to JSON Schema Generator
Infer a JSON Schema from example data for validation, documentation and OpenAPI.
Input
1
Result
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Original (left)
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Modified (right)
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Differences
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About this tool
How the JSON to JSON Schema works
Generate a JSON Schema (draft 2020-12) from example JSON: types, required keys, nested objects, array items and formats like date-time, uuid and uri.
How to use the JSON to JSON Schema
- Paste example JSON (several array items give better results).
- Set a title and choose strict mode if needed.
- Copy or download the schema.
JSON to JSON Schema example
{"id":7,"name":"aarav","tags":["a"]}{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"title": "User",
"type": "object",
"properties": {
"id": {
"type": "integer"
},
"name": {
"type": "string"
},
"tags": {
"type": "array",
"items": {
"type": "string"
}
}
},
"required": [
"id",
"name",
"tags"
]
}When to use it
- Validating API payloads with Ajv or other validators.
- Writing OpenAPI 3.1 component schemas.
- Enabling autocomplete for JSON config files in VS Code.
Tip: Add descriptions, enums and minimum/maximum values by hand afterwards; examples cannot reveal those rules.
Formats
date-time, date, uuid and uri formats are detected from string values.
Integer vs number
Whole numbers become integer; decimals become number.
Strict mode
Optionally add additionalProperties: false to reject unknown keys.
FAQ
Common questions
Which draft is generated?
JSON Schema draft 2020-12, the version used by OpenAPI 3.1. Most validators, such as Ajv, support it.
How are arrays described?
items holds one schema merged from all elements, so optional item fields are detected.
How is null handled?
Values that are sometimes null get a type list such as ["string", "null"].
Is it private?
Yes, the schema is generated in your browser.
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