How are nested objects handled?

Each nested object becomes its own TypeScript interface with a PascalCase name derived from the key. The parent interface references the child interface by name.

What happens with null values?

Fields with null values are typed as `field?: type | null`. If the field is always null the tool falls back to `null` type. You can refine this after generation.

Are arrays supported?

Yes. Array element types are inferred from the first element. An empty array produces `unknown[]`. Mixed-type arrays produce a union type.

JSON to TypeScript

Convert JSON to TypeScript interfaces with proper type inference.

$json input

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$typescript interfaces[READY]

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FAQ

How are nested objects handled?: Each nested object becomes its own TypeScript interface with a PascalCase name derived from the key. The parent interface references the child interface by name.
What happens with null values?: Fields with null values are typed as `field?: type | null`. If the field is always null the tool falls back to `null` type. You can refine this after generation.
Are arrays supported?: Yes. Array element types are inferred from the first element. An empty array produces `unknown[]`. Mixed-type arrays produce a union type.

Paste any JSON object and instantly generate TypeScript interface definitions. The tool recursively walks the JSON structure, infers types (string, number, boolean, null, arrays, nested objects), marks nullable fields as optional, and names the top-level interface "Root". Nested objects become separate named interfaces.