JSON Schema Generator
Generate JSON Schema Draft-07 from any JSON example with type inference and format detection
Enter a JSON example to generate a JSON Schema (Draft-07) from its structure
What is the JSON Schema Generator?
The JSON Schema Generator infers a complete JSON Schema (Draft-07) from any JSON example you provide. It automatically detects types, marks required fields, recognizes common string formats (email, URI, UUID, date-time, IPv4, IPv6), and handles nested objects and arrays — all processed entirely in your browser.
How to Use
- Paste a JSON example into the input field
- Click "Generate Schema" or wait for automatic processing
- Review the generated JSON Schema in the output panel
- Copy the schema or export it as a JSON file
Example: User Object
Given this JSON input:
{
"id": 1,
"name": "John Doe",
"email": "john@example.com",
"active": true
}The generator produces:
{
"$schema": "http://json-schema.org/draft-07/schema#",
"type": "object",
"properties": {
"id": { "type": "integer" },
"name": { "type": "string" },
"email": { "type": "string", "format": "email" },
"active": { "type": "boolean" }
},
"required": ["id", "name", "email", "active"]
}Features
- Type inference — Detects string, number, integer, boolean, null, object, and array types
- Required fields — All present keys are marked as required; for arrays of objects, only keys in every item are required
- Array homogeneity — Detects whether array items share the same structure or vary
- Format detection — Recognizes date-time, date, email, URI, UUID, IPv4, and IPv6 string formats
- Nested structures — Recursively generates schemas for deeply nested objects and arrays
- Draft-07 compliance — Output is a standards-compliant JSON Schema usable with any validator
Use Cases
- Bootstrap API contracts from example payloads
- Generate validation schemas for configuration files
- Document data structures for team collaboration
- Create form validation rules from sample data
- Validate incoming webhook payloads against expected structure
Privacy
All schema generation happens entirely in your browser using JavaScript. Your JSON data never leaves your device and is not stored, logged, or transmitted to any server.
Frequently Asked Questions
What does the JSON Schema Generator do?
It takes a JSON example and automatically infers a JSON Schema (Draft-07) describing its structure. It detects types (string, number, integer, boolean, null, object, array), marks all present keys as required, detects array homogeneity, and recognizes common string formats like date-time, email, URI, UUID, and IP addresses.
Which JSON Schema draft does it generate?
The tool generates schemas conforming to JSON Schema Draft-07 (http://json-schema.org/draft-07/schema#). Draft-07 is widely supported by validators, code generators, and API tools.
How are required fields determined?
All keys present in an object are marked as required. For arrays of objects, only keys that appear in every array item are marked as required in the items schema. This ensures the generated schema accurately reflects the structure of your example data.
What is array homogeneity detection?
When the tool encounters an array, it checks whether all items share the same type and structure. If they do (homogeneous), it generates a single 'items' schema. If items have different types (heterogeneous), it merges the schemas to cover all observed variations using type arrays.
Is my JSON data sent to a server?
No. All schema generation happens entirely in your browser using JavaScript. Your JSON data never leaves your device and is not stored, logged, or transmitted to any server.
Does it detect string formats automatically?
Yes. The tool detects common string formats including date-time (ISO 8601), date, email, URI/URL, UUID, IPv4, and IPv6. Detected formats are included in the schema using the 'format' keyword, which validators can use for additional validation.
Can I validate my JSON against the generated schema?
Yes. Copy the generated schema and use a JSON Schema validator (like the JSON Schema Validator tool on this site) to validate other JSON documents against it. The schema is standards-compliant and works with any Draft-07 compatible validator.
What happens with nested objects and arrays?
The tool recursively traverses your entire JSON structure, generating nested schemas for objects within objects, arrays within arrays, and any combination. Each level of nesting produces its own schema with appropriate type information and required fields.
What is the maximum input size?
The tool warns at 500KB and rejects input larger than 5MB. For most practical use cases, JSON examples are well under these limits. If your input is very large, consider using a representative subset of your data.