JSON to JSON Schema Converter
Convert JSON objects to JSON Schema for validation and documentation. Automatically detects types, formats, and generates complete schema definitions. Supports Draft 7, 2019-09, and 2020-12 specifications.
Schema Options
Recommended Settings
JSON Schema Best Practices
- •Use Draft 7 for maximum compatibility with existing validators and tools
- •Include descriptions to make your schema self-documenting for API consumers
- •Mark truly required fields only - avoid marking all fields as required
- •Use format validators (email, uri, date-time) to catch common data errors
- •Include examples to help developers understand expected data structures
Schema Version Selection Guide
- •Draft 7: Best for broad compatibility, most widely supported by validators
- •Draft 2019-09: Recommended for new projects, adds modern validation features
- •Draft 2020-12: Latest features but limited validator support currently
- •All versions support core features: type validation, properties, required fields
- •Choose based on your validator library support and project requirements
Pro Tips
- •Paste JSON and it auto-validates - schema generation happens automatically when valid
- •Format detection identifies email, URI, date-time, and UUID patterns automatically
- •Use 'Mark all required' cautiously - it makes the schema strict for all fields
- •All processing happens in your browser - your data never leaves your device
Most Popular
Most users generate Draft 7 schemas with format detection and examples enabled
When to Use This Tool
Generate JSON Schema from sample API responses to validate data consistency. Use the schema to ensure API responses match expected structure, catch type errors early, and document API contracts. Perfect for REST APIs, webhooks, and microservices communication.
Create schema definitions for OpenAPI specifications from example request/response bodies. JSON Schema is the core of OpenAPI's data modeling. Generate schemas from real data samples to quickly build accurate API documentation and enable automatic client generation.
Build dynamic forms with validation from JSON Schema definitions. Many UI libraries (React Hook Form, Formik, JSON Forms) can generate forms and validation rules from JSON Schema. Convert your data model to schema and auto-generate validated form components.
Validate data quality by generating schemas from correct examples and testing against datasets. Use schemas in unit tests to ensure data transformations preserve structure. Catch breaking changes in data pipelines by comparing against validated schemas.
How It Works
Paste your JSON data into the input field on the left side
Select your preferred JSON Schema version (Draft 7, 2019-09, or 2020-12)
Choose generation options: required fields, examples, format detection, descriptions
The tool automatically validates JSON syntax and detects data types
Strings are analyzed for common formats: email, URI, date-time, UUID
Arrays are detected with homogeneous or heterogeneous item schemas
Nested objects generate complete nested schema definitions
The final schema includes $schema declaration and all detected properties
Copy the schema to clipboard or download it as a .json file
All processing happens in your browser - your JSON data never leaves your device
100% Private
Files never leave your device. All processing happens locally in your browser.
Lightning Fast
Powered by Pure JavaScript for optimal performance on modern browsers.
Secure
No data collection, no tracking, no sign-up required.
Frequently Asked Questions
What is JSON Schema?
JSON Schema is a vocabulary that allows you to annotate and validate JSON documents. It describes the structure, data types, constraints, and relationships in your JSON data. JSON Schema is used for validation, documentation, code generation, and form building across many programming languages and frameworks.
Which JSON Schema version should I use?
Use Draft 7 for maximum compatibility - it's supported by virtually all validators and tools. Draft 2019-09 is recommended for new projects as it includes modern features while maintaining good validator support. Draft 2020-12 is the latest but has limited tooling support currently. Choose based on your validation library requirements.
How does format detection work?
The tool analyzes string values using regex patterns to detect common formats: email (user@domain.com), URI (http://...), date-time (ISO 8601), and UUID (8-4-4-4-12 hex). Detected formats are added to the schema which enables validators to check not just type but also format validity. Disable format detection if you want generic string types.
What does 'Mark all required' do?
Enabling this option adds all object properties to the 'required' array in the schema. This means validators will reject data missing any field. Use this when all fields are truly mandatory. For optional fields, leave this disabled and manually specify required fields later, or generate multiple schemas from different data samples.
Can I use this schema with TypeScript or other languages?
Yes! JSON Schema is language-agnostic. You can use it with TypeScript via json-schema-to-typescript, with Python via jsonschema library, with Java via jackson-module-jsonSchema, and many others. The schema serves as a single source of truth for data validation across your entire tech stack.
How are arrays handled in the schema?
The tool examines array items to detect homogeneous types (all items same type). If all items match, a single 'items' schema is generated. For heterogeneous arrays (mixed types), an empty items schema is created. Nested objects in arrays get full schema definitions. Array validation can include minItems, maxItems, and uniqueItems in post-processing.
What are example values used for?
Example values in JSON Schema show developers what valid data looks like. They're documentation, not validation - validators don't enforce them. Examples help with: API documentation, code generation tools that create sample data, understanding expected formats, and testing schema validators. Disable if you don't want actual values in the schema.
Is my JSON data secure using this tool?
Yes, your data is completely private. All schema generation happens entirely in your browser using JavaScript - nothing is sent to any server. Your JSON never leaves your device. The generated schema is also local-only until you choose to copy or download it. No tracking, no storage, no transmission.