JSON Schema Generator Online
Paste a JSON object and instantly generate its corresponding JSON Schema. The tool runs entirely in your browser — your data never leaves your device.
JSON Schema Validator
Validate JSON data against a JSON Schema (Draft 07) with detailed error reporting. Generate schemas from sample data or load examples to get started.
JSON Schema Quick Reference
JSON Schema is a vocabulary for annotating and validating JSON documents. It describes the structure, constraints, and documentation of JSON data.
type— Data type: string, number, integer, boolean, object, array, nullrequired— Array of required property namesproperties— Object property schemasitems— Schema for array elementsenum— Allowed valuespattern— Regex pattern for stringsminimum / maximum— Number range constraintsminLength / maxLength— String length constraintsformat— Semantic format: email, uri, date-time, ipv4, uuid, etc.additionalProperties— Allow or deny extra properties on objects
allOf— Must match all schemasanyOf— Must match at least one schemaoneOf— Must match exactly one schemanot— Must not match the schema
This tool supports JSON Schema Draft 07 with format validation (email, URI, date-time, etc.) via ajv-formats. Everything runs in your browser — no data is sent over the network.
What is a JSON Schema?
JSON Schema is a vocabulary that lets you annotate and validate the structure of JSON documents. It defines expected data types, required properties, value constraints, and nested object shapes. JSON Schema is used in API documentation (OpenAPI/Swagger), form validation, configuration file validation, and data pipeline contracts.
Common use cases
Developers generate schemas to bootstrap API validation middleware, create OpenAPI definitions from example payloads, enforce data contracts between microservices, and auto-generate TypeScript types. Generating a schema from an existing JSON sample is much faster than writing one by hand, especially for complex nested structures.
Frequently Asked Questions
How accurate is the auto-generated schema?
The generator infers types and required fields from your sample data. It produces a valid schema that matches your input structure. You may want to fine-tune constraints like minLength, patterns, or enums for production use.
Which JSON Schema draft does the generator use?
The generator produces schemas compatible with Draft-07, the most widely supported draft across validation libraries, OpenAPI 3.0, and tooling ecosystems.