JSON Schema Generator - Online JSON to Schema Converter
JSON Schema is an established IETF standard used to annotate and validate JSON documents. When building microservices or exposing public APIs, defining a JSON Schema guarantees that incoming client request bodies conform to expected properties, required fields, and primitive types. This tool inspects your JSON instance and generates a compliant JSON Schema specification instantly.
When to Use This Tool
- API Request Validation: Generate validation schemas for frameworks using Ajv, Zod, or Express validator.
- OpenAPI & Swagger Specs: Create component schema models to document REST endpoints in OpenAPI 3.0 YAML/JSON.
- Data Contract Enforcement: Define rigid schemas between microservice message queues (Kafka, RabbitMQ) to avoid serialization bugs.
- Automated Testing Payloads: Verify that backend API test suites receive payloads strictly conforming to the contract.
How to Use
- Input Sample JSON: Paste a representative JSON payload containing the fields you want in the schema.
- Generate Schema: Click generate to analyze property types, required keys, and array structures.
- Inspect Specifications: Review the generated JSON Schema with "$schema", "type", "properties", and "required".
- Export & Implement: Copy the schema into your backend validation files or download it as schema.json.
Input & Output Example
Input:
{
"productId": 456,
"productName": "DevToolz Pro",
"inStock": true
}
Output:
{
"$schema": "http://json-schema.org/draft-07/schema#",
"type": "object",
"properties": {
"productId": {
"type": "integer"
},
"productName": {
"type": "string"
},
"inStock": {
"type": "boolean"
}
},
"required": [
"productId",
"productName",
"inStock"
]
}
Frequently Asked Questions (FAQ)
Q. Which JSON Schema draft standard is generated?
A. It outputs standard Draft-07 by default, which is the most widely supported draft across modern backend validation engines like Ajv and OpenAPI 3.0.
Q. Does it automatically mark all properties as "required"?
A. By default, present keys are categorized under the "required" array to encourage strict data validation. You can easily remove optional fields from the required list in your code.
Q. Can it detect specific string formats like date-time or email?
A. Common patterns (ISO dates, emails) can be enriched with "format": "date-time" or "format": "email" according to your API validation requirements.
Engineering & Privacy Notes
- Pure client-side execution ensures your API schemas and business payloads remain 100% confidential.
- Outputs clean, validated JSON Schema compatible with modern backend microservices.
Related Developer Tools
- JSON Formatter: Validate and format raw JSON before drafting schema definitions.
- JSON to TypeScript: Convert JSON to static compile-time TypeScript types alongside JSON Schema.
- Diff Checker: Compare schema versions to detect breaking API changes.
- JWT Decoder: Inspect and model JSON schemas for authorization token payloads.