JSON Schema Generator - Generate JSON Schema from JSON

JSON Input

Generated Schema

What is JSON Schema Generator?

Ever needed to document your API's data structure but didn't want to write a JSON Schema by hand? That's where this tool comes in. Just paste your JSON (JavaScript Object Notation) data, and we'll automatically generate a complete schema that describes its structure, types, and validation rules.

Perfect for API documentation, data validation, or just understanding what your JSON actually contains. As MDN Web Docs explains, JSON Schema helps validate data structures, and our generator follows the official JSON Schema specification. It handles nested objects, arrays, and all the tricky parts automatically.

Best part? It all happens in your browser – your data never leaves your computer. No uploads, no waiting, just instant schema generation.

What Makes This Tool Different

Automatic Schema Generation

Just paste your JSON and we'll figure out the schema for you. It detects all the types, handles nested objects and arrays, and even figures out which fields are required.

Type Detection

We automatically figure out whether something's a string, number, boolean, object, or array. It also handles null values and knows when fields might be optional.

Nested Structure Support

Got deeply nested JSON? No problem. We handle objects within objects, arrays of objects, and all those complex structures you'd rather not think about.

File Upload Support

Don't want to copy-paste? Just upload your .json or .txt file. Works great for those massive API responses or config files.

Copy & Download

One click to copy, or download it as a file. Drop it straight into your API docs or validation setup – it's ready to go.

Syntax Highlighting

Both your input JSON and the generated schema get nice syntax highlighting. Makes it way easier to spot issues and verify everything looks right.

How It Works

Paste or Upload JSON

Drop your JSON into the left editor, or upload a file if you prefer. Not sure what to expect? Hit "Sample" to see how it works. Works with objects or arrays – whatever you've got.

Automatic Schema Generation

We analyze your JSON and spit out a complete schema in the right panel. It includes all the types, properties, and structure info you need.

Copy or Download

Take a quick look to make sure it's what you need, then copy it to your clipboard or download it. Drop it into your API docs or validation setup and you're done.

When You'd Actually Use This

API Documentation

Got an API response example? Generate a schema from it and use it in your Swagger/OpenAPI docs. Way faster than writing schemas by hand.

Data Validation

Need to validate incoming JSON? Generate a schema and use it with validation libraries to make sure your data matches what you expect.

Type Definitions

Generate schemas to understand data structures. Perfect for documenting complex JSON formats or understanding API contracts.

Contract Testing

Create schemas for contract testing. Verify that API responses match expected structures using schema validation.

Common Questions

Is my JSON data stored?

Nope. Everything happens right in your browser. Your JSON never leaves your computer – we don't even see it.

What JSON Schema version is used?

We generate schemas that work with JSON Schema Draft 7 and newer. Everything follows the official spec, so it'll work with standard validation tools.

Does it handle arrays?

Absolutely. Arrays are no problem. If you've got an array of objects, we'll analyze the object structure and create the right item schema for you.

What about optional vs required fields?

We look at your JSON sample and figure out which fields show up every time. Those get marked as required, while fields that sometimes appear are marked optional.

Can I edit the generated schema?

Sure thing. The output panel is fully editable, so you can tweak types, add constraints, or adjust anything to fit your needs.

Does it work with invalid JSON?

Nah, you'll need valid JSON first. If something's broken, we'll show you an error. Try our JSON Validator or JSON Fixer to sort it out first.

Other JSON Tools You Might Need

Schema generation is just one thing you might need. Here are some other tools that work great together:

Want to learn more about JSON? The JSON.org site is a great place to start, or check out the guide on MDN.