JSON Schema Generator
Infer a JSON schema from an example payload, with format detection and required-key heuristics.
Free & unlimited
Dialect
Required keys
Examples
Input JSON
Generated schema
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"type": "object",
"properties": {
"name": {
"type": "string"
},
"age": {
"type": "integer"
},
"email": {
"type": "string",
"format": "email"
},
"roles": {
"type": "array",
"items": {
"type": "string"
}
}
},
"required": [
"age",
"email",
"name",
"roles"
]
}
All processing happens in your browser. No data is sent to any server.
About this tool
- 1
Paste your JSON
Enter a sample JSON object or array that represents your data structure.
- 2
Configure schema options
Choose the JSON Schema draft version and whether to include descriptions or mark fields as required.
- 3
Review the schema
Inspect the generated schema to verify types, required fields, and validation rules are correct.
- 4
Export
Copy the schema or download it as a .json file for use in your validation pipeline.
- Provide a complete sample with all possible fields filled in - the generator can only infer types from values it sees.
- Null values result in ambiguous types; use a non-null example value when possible.
- Array items are analyzed to determine if they share a common schema or need a union type.
- After generating, manually add constraints like minimum, maximum, pattern, and enum for tighter validation.
- Supports JSON Schema Draft 4, 6, 7, and 2020-12
- Infers types, required fields, and nested object schemas
- Detects array item types and generates array schemas
- Produces well-structured $ref definitions for reusable schemas
- Syntax-highlighted output with collapsible sections
- Generate validation schemas for REST API request and response bodies
- Create JSON Schema definitions for form validation in frontend frameworks
- Bootstrap schema files for configuration validation in CI/CD pipelines
- Document data structures by generating schemas from example payloads
Draft 7 is the most widely supported. Use Draft 2020-12 for the latest features if your validation library supports it.
Paste multiple examples and the tool will merge them to create a schema that covers all observed field types and optionality.
By default, all fields present in the sample are marked required. You can toggle individual fields to optional after generation.