import BaseLayout from '@versal/ui/BaseLayout'; const title = 'JSON to TypeScript Interface'; const description = 'Convert JSON data into clean TypeScript interfaces. Includes nested types, optional fields, arrays, and union types. Runs entirely in your browser.'

{title}

{description}

Input JSON

TypeScript Interface

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Error

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How it works

Paste any valid JSON on the left.
Click Convert to TypeScript — the interface appears instantly.
All types are inferred from the JSON values: numbers, strings, booleans, arrays, objects, and null.
Click Make all optional to prefix every field with ?.

Type mapping rules

JSON value	TypeScript type
`42`, `3.14`	`number`
`"hello"`	`string`
`true` / `false`	`boolean`
`null`	`null`
`[1, 2, 3]`	`number[]`
`[{...}, {...}]` (array of objects)	`NestedType[]`
`{"a": 1}`	`NestedObject { a: number }`