📖 What is JSON Schema Generator?
JSON Schema Generator analyzes a JSON sample and produces a JSON Schema definition that describes its structure — including types, required properties, nested objects and array item types. Use it to quickly create validation schemas for APIs, form inputs or configuration files without writing the schema by hand. Everything runs in your browser.
💡 Example
Input
{"name":"Alice","age":30,"email":"alice@example.com"}
Output
{"type":"object","properties":{"name":{"type":"string"},"age":{"type":"integer"},"email":{"type":"string"}},"required":["name","age","email"]}
🛠️ Common Use Cases
- Creating JSON Schema for REST API request/response validation
- Generating schemas for OpenAPI/Swagger documentation
- Building form validation rules from JSON data models
- Documenting data structures for team communication
- Creating config file validation schemas
📝 What Gets Inferred
- Types — string, integer, number, boolean, null, object, array
- Required fields — all present fields are marked as required by default
- Nested objects — generate sub-schemas for nested structures
- Array item types — detects the type of array elements
The generated schema uses JSON Schema Draft-07 format, compatible with most validators.
⚠️ Common Mistakes
- Using incomplete samples — optional fields missing from your sample won't appear in the schema. Use the most complete JSON available.
- Single-item arrays — the item type is inferred from the first element. Mixed-type arrays need manual adjustment.
- Over-constraining — generated schemas mark all fields as required. Review and mark truly optional fields.
❓ Frequently Asked Questions
Which JSON Schema version is generated? ▾
The output follows JSON Schema Draft-07, which is widely supported by validators, OpenAPI 3.0, and most programming language libraries.
Can I use the schema with OpenAPI/Swagger? ▾
Yes — JSON Schema is the foundation of OpenAPI schema definitions. Paste the generated schema into your OpenAPI spec's components/schemas section.
How do I mark fields as optional? ▾
Remove field names from the "required" array in the generated schema. Fields not listed in "required" are treated as optional by validators.
Is my data private? ▾
Yes — all processing runs entirely in your browser. Your data is never sent to any server.
Is this tool free? ▾
Completely free — no login, no usage limits, works offline once loaded.
Yes — completely free, no login required, no usage limits.
Is my data private? ▾
Yes — all processing runs in your browser. Your data is never sent to any server.
Does it work offline? ▾
Yes — once the page is loaded, the tool works without an internet connection.