INPUT - JSON
OUTPUT - TypeScript
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100% client-side
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Convert JSON to TypeScript interfaces in one click with our free online JSON to TypeScript converter. The tool infers proper types for every field, generates named interfaces for nested objects, and supports strict-mode-compatible output. Ideal for front-end developers who need typed API response models without writing boilerplate.
Try Convert All - paste JSON once, see TypeScript, Go, YAML, and 15 more formats instantly.
Enter a JSON object or array in the left editor, or fetch JSON from a URL. The converter accepts any valid JSON structure including deeply nested data.
The right pane instantly displays TypeScript interfaces with properly inferred types for strings, numbers, booleans, arrays, and nested objects.
Click Copy to place the interfaces on your clipboard, or download the generated code as a .ts file ready to drop into your project.
The converter produces string, number, boolean, null, and nested interface types. When an array holds mixed primitives it creates a union type such as string | number. Date-like strings remain typed as string since TypeScript interfaces describe raw JSON shapes.
Yes. Every nested object generates its own named interface, and the parent interface references it by name. This keeps code clean and avoids inline type literals, even for three or four levels of nesting.
Absolutely. Use the URL-fetch button to pull a live JSON response from any public API endpoint. The converter will parse the response and produce TypeScript interfaces immediately, saving you from writing types by hand.
Yes, and this is checked rather than claimed: every fixture in the repository is compiled with tsc --strict on each run. A field seen as null is typed T | null, and a key absent from some records is marked optional with ?, so strictNullChecks flags unchecked access in both cases.
Top-level objects use the name "Root" by default. Nested objects are named after their parent key in PascalCase. For example, a key called "shipping_address" produces an interface named ShippingAddress.