Is my JSON data uploaded to a server?

No. The conversion runs entirely in your browser with JavaScript. Nothing is sent over the network, which makes the tool safe for sensitive data.

How are nested objects handled?

Each nested object becomes its own GraphQL type in the generated SDL, referenced from its parent type.

What happens with null values or mixed arrays?

They are typed with a custom JSON scalar, and the scalar declaration is only emitted when it is actually needed. All other fields are non-null by default.

100% local — your data never leaves your browser

JSON to GraphQL Schema Converter — Free Online Tool

Generate GraphQL SDL types from sample JSON instantly in your browser. Free, private and offline-friendly: your data never leaves your device.

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Root name

JSON input

GraphQL output

Why convert JSON to GraphQL?

Designing a GraphQL schema from an existing API payload by hand takes time. Paste a sample JSON document above and get ready-to-use SDL type definitions in milliseconds, with one type per nested object.

How it works

The converter parses your JSON locally and emits GraphQL SDL: one type per nested object, with fields marked non-null (!) by default. Null values and heterogeneous arrays fall back to a custom JSON scalar, which is declared only when needed.

Frequently asked questions

Is my JSON data uploaded to a server?: No. The conversion runs entirely in your browser with JavaScript. Nothing is sent over the network, which makes the tool safe for sensitive data.
How are nested objects handled?: Each nested object becomes its own GraphQL type in the generated SDL, referenced from its parent type.
What happens with null values or mixed arrays?: They are typed with a custom JSON scalar, and the scalar declaration is only emitted when it is actually needed. All other fields are non-null by default.