JSON Schema Generator

Generate JSON Schema from your data or validate JSON against an existing schema

JSON Schema Generator

Draft Version

Mark all fields as required

Allow additional properties

JSON Input

JSON Data

JSON Schema

100% client-side. Your JSON data never leaves your browser.

Usage Examples

Use Draft-07 for the latest features including conditional schemas and content encoding.

Enable "Mark all fields as required" when you need strict validation of mandatory fields.

Download the generated schema and add it to your project for automated CI validation.

Paste a sample API response to quickly scaffold a schema for your documentation.

JSON Schema Types

Supported JSON Schema data types:

string - Text values
number - Decimal numbers
integer - Whole numbers
boolean - true/false
array - Ordered lists
object - Key-value pairs
null - Null value

Features

Auto Schema Generation

Paste any JSON and get a complete schema with types, formats, and structure detected automatically

Schema Validation

Validate JSON data against any schema and see detailed error messages for mismatches

Multiple Draft Versions

Support for Draft-04, Draft-06, and Draft-07 to match your project requirements

Private & Offline

Runs entirely in your browser, no JSON data is sent to any server

How to Use

Paste Your JSON

Paste your JSON data into the input area or try one of the provided examples.

Configure Options

Select the draft version and toggle options like required fields and additional properties.

Generate or Validate

Click Generate Schema to create a schema, or switch to the Validate tab to check JSON against a schema.

Frequently Asked Questions

JSON Schema is a vocabulary for annotating and validating JSON documents. It describes the expected structure, data types, required fields, and constraints of your JSON. A schema document is itself JSON and can be used to auto-validate API payloads, form inputs, config files, or database records. It is the foundation of OpenAPI/Swagger specifications and widely used in CI pipelines for data contract testing.

Paste any valid JSON and click Generate Schema. The tool walks through every property recursively, infers types (string, number, integer, boolean, null, object, array), detects common string formats (date-time, email, URI, UUID), and produces a complete schema tree. Options let you mark all fields as required, disallow additional properties, or add description placeholders for documentation.

Draft-07 is the right choice for most projects — it is the most widely supported version and adds features like if/then/else conditionals and content encoding keywords. Draft-06 introduced "const" and "contains". Draft-04 is the oldest and should only be used if a specific tool (older validators, some Swagger 2.0 tooling) explicitly requires it. When in doubt, use Draft-07.

Yes. Switch to the Validate tab, paste your JSON data in the left panel and your schema in the right panel, then click Validate. The tool runs the full validation and reports each error with the field path and violation description. This lets you check JSON from an API, a form submission, or a config file against any schema — not just ones generated by this tool.

The required keyword lists fields that must be present in the JSON. When you enable "Mark all fields as required", every key found in your sample JSON is added to the required array. In practice, you will usually edit this list after generation — remove keys that are truly optional. A field being required means validation fails if that key is absent; it says nothing about the field's value being non-null.

When additionalProperties is set to false in the schema, validation rejects any JSON that contains keys not defined in the properties object. This is useful for strict API contracts where you want to catch typos in field names or prevent clients from sending undeclared fields. Leaving it at true (or omitting it) allows any extra fields without validation errors — better for forward-compatible schemas.

Download or copy the schema, then use a validation library: Ajv (JavaScript/Node.js), jsonschema or jsonschema-rs (Python/Rust), Newtonsoft.Json.Schema (C#), or NetworkNT JSON Schema Validator (Java). In Ajv: const validate = ajv.compile(schema); const valid = validate(data). The schema file can also be referenced in OpenAPI specs under components/schemas for auto-generated documentation.

Yes. This tool runs 100% in your browser. Your JSON data is never sent to any server, stored, or logged. You can safely use it with API responses containing credentials, internal config files, or any sensitive data.

What is a JSON Schema Generator?

A JSON Schema Generator automatically creates a JSON Schema definition from sample JSON data. Instead of writing schema definitions by hand, you paste your JSON and the tool infers types, structures, nested objects, and arrays to produce a valid schema document. This saves hours of manual work and reduces the chance of errors in your schema definitions.

How It Works

The generator parses your JSON input and walks through every property recursively. It detects data types (string, number, integer, boolean, null, object, array), identifies string formats like dates and emails, and builds a complete schema tree. You can customize the output with options for required fields, additional properties, and description placeholders. Everything runs client-side in your browser.

Common Use Cases

Developers use JSON Schema generators to document REST APIs, validate configuration files, enforce data contracts between microservices, and build form validators. Schemas generated from real API responses serve as living documentation that can be tested automatically in CI pipelines. They are also essential for OpenAPI and Swagger specifications.

Privacy and Security

This JSON Schema Generator is 100% client-side. All parsing, schema generation, and validation happen in your browser using JavaScript. No JSON data is sent to any server. No cookies track your input, and nothing is stored beyond your current session. Safe to use with proprietary APIs, internal configurations, and sensitive data.

Security and Privacy

Your data security is our priority

Local Processing

All processing happens in your browser

No Data Transfer

Your data is not sent to our servers

No Data Storage

No data is stored or shared

SSL Encryption

SSL encryption for secure connection

Was this tool useful?

JSON Schema Generator