How to use this tool
- Paste JSON, upload a local file, or load a CORS-enabled public URL.
- Paste a representative sample and run Generate JSON Schema.
- Review the result, then copy it or download it with the correct file type.
Private by default
JSON Schema Generator from Sample
Generate object properties, required keys, primitive types, and array item candidates.
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AuditableDocumented semantics
PortableCorrectly typed downloads
Category
JSON Schema Generator: How to use this tool
Infer a deterministic JSON Schema Draft 2020-12 starting point from one valid sample.
Generate object properties, required keys, primitive types, and array item candidates.
Open guide and examples
Example to try
Input JSON
{
"users": [
{"id": 1, "name": "Ada"},
{"id": 2, "active": true}
],
"values": [1, "two", null, true],
"metadata": {
"createdAt": "2026-08-18T08:00:00Z",
"page": 1
}
}Result
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"type": "object",
"properties": {
"metadata": {
"type": "object",
"properties": {
"createdAt": {
"type": "string"
},
"page": {
"type": "integer"
}
},
"required": [
"createdAt",
"page"
]
},
"users": {
"type": "array",
"items": {
"type": "object",
"properties": {
"active": {
"type": "boolean"
},
"id": {
"type": "integer"
},
"name": {
"type": "string"
}
},
"required": [
"id"
]
}
},
"values": {
"type": "array",
"items": {
"anyOf": [
{
"type": "boolean"
},
{
"type": "integer"
},
{
"type": "null"
},
{
"type": "string"
}
]
}
}
},
"required": [
"metadata",
"users",
"values"
]
}Learn
Frequently asked questions
Does this tool upload my JSON?
No. The transformation runs in your browser. URL import contacts only the address you explicitly enter.
What happens when the JSON is invalid?
The editor marks the likely location and keeps stale output out of the result pane.
What does JSON Schema Generator produce?
It emits a starter Draft 2020-12 schema inferred only from values present in the sample.
What limitation applies to JSON Schema Generator?
One sample cannot reveal optional fields, formats, numeric bounds, string patterns, or business rules; review the schema.