SDL (Schema Definition Language) is the standard syntax for defining GraphQL schemas. It describes your data types, fields, and their relationships in a human-readable format.

Can I generate input types for mutations?

Yes. Toggle the "Generate input types" option to create separate GraphQL input types alongside the regular types, which are useful for mutation arguments.

How are nested objects handled?

When a property contains a nested object, the converter creates a separate named type (e.g., UserAddress) and references it in the parent type, following GraphQL best practices.

Does it support non-null modifiers?

Yes. Enable the "Non-null fields" option to add the ! modifier to all fields, indicating they are required in your GraphQL schema.

Is my JSON data kept private?

Absolutely. All JSON parsing and GraphQL schema generation happens entirely in your browser. No data is ever sent to any server.

JSON to GraphQL Schema

Convert JSON objects into GraphQL schema type definitions instantly.

100% free
Private in browser
No signup
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JSON Payload

GraphQL Schema

2 types generated

type Address {
  street: String
  city: String
  country: String
}

type User {
  id: Int
  name: String
  email: String
  isActive: Boolean
  score: Float
  roles: [String]
  address: Address
}

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About JSON to GraphQL Schema

JSON to GraphQL Schema Converter on TheToolss transforms JSON objects, API responses, and sample payloads into valid GraphQL SDL type definitions. It recursively traverses nested objects to create separate types, infers scalar types from values, handles arrays, and supports optional input type generation. All processing runs client-side in your browser — no data leaves your device.

How to use JSON to GraphQL Schema

Paste your JSON payload or API response into the input box.
Configure the root type name and optional settings like input types and non-null fields.
View the generated GraphQL schema and copy it to your clipboard.

Key features

Generates clean GraphQL SDL type definitions from any JSON structure
Recursively creates separate types for nested objects
Handles arrays, nullable values, and mixed types
Optional input type generation for mutations
Non-null (!) modifier support for required fields
100% private — all processing happens in your browser

Frequently asked questions

What is GraphQL SDL?: SDL (Schema Definition Language) is the standard syntax for defining GraphQL schemas. It describes your data types, fields, and their relationships in a human-readable format.
Can I generate input types for mutations?: Yes. Toggle the "Generate input types" option to create separate GraphQL input types alongside the regular types, which are useful for mutation arguments.
How are nested objects handled?: When a property contains a nested object, the converter creates a separate named type (e.g., UserAddress) and references it in the parent type, following GraphQL best practices.
Does it support non-null modifiers?: Yes. Enable the "Non-null fields" option to add the ! modifier to all fields, indicating they are required in your GraphQL schema.
Is my JSON data kept private?: Absolutely. All JSON parsing and GraphQL schema generation happens entirely in your browser. No data is ever sent to any server.