JSON to JSON Schema generator
Convert any JSON sample to a JSON Schema (draft-06). Cross-language contract for validation, code generation, and documentation tooling.
# context
JSON Schema is the lingua franca for describing JSON shape across languages. Once you have a schema, every language with a generator (this tool, quicktype CLI, openapi-generator, json-schema-to-typescript, etc) can derive types in its native style. This is the path to take when you want one source of truth for an API contract.
JSON input
{
"id": 1,
"name": "Ada Lovelace",
"email": "[email protected]",
"active": true,
"roles": ["admin", "engineer"],
"createdAt": "2026-05-14T00:00:00Z"
}Output preview
{
"$schema": "http://json-schema.org/draft-06/schema#",
"$ref": "#/definitions/User",
"definitions": {
"User": {
"type": "object",
"additionalProperties": false,
"properties": {
"id": { "type": "integer" },
"name": { "type": "string" },
"email": { "type": "string", "format": "email" },
"active": { "type": "boolean" },
"roles": { "type": "array", "items": { "type": "string" } },
"createdAt": { "type": "string", "format": "date-time" }
},
"required": ["id", "name", "email", "active", "roles", "createdAt"]
}
}
}→ Open in JSON to Types generator (pre-filled)
# notes
- Output uses draft-06. For draft 2020-12, hand-edit the `$schema` URL after generation — the shape is mostly compatible.
- Email and date-time formats are inferred from the value shape. Add `pattern` regex constraints by hand for tighter validation.
- JSON Schema is the recommended source-of-truth for multi-language code generation — generate it once, then feed it to per-language generators.