How does JSON to TypeScript conversion work?

Paste a JSON object and the tool analyzes the structure, data types, and nesting to generate TypeScript interfaces. Arrays are typed based on their contents, and nested objects get their own named interfaces.

Does it handle optional fields?

The tool generates interfaces based on the sample data provided. If a field is present, it's marked as required. For optional fields, you'll need to add the ? modifier manually after reviewing the generated types.

Can I generate types from API responses?

Absolutely — that's one of the most popular uses. Copy a JSON API response, paste it in, and get TypeScript interfaces ready to use in your frontend code. This saves significant time when working with REST APIs.

What TypeScript types are generated for JSON values?

Strings become string, numbers become number, booleans become boolean, null becomes null, arrays become typed arrays (e.g., string[]), and objects become named interfaces with all their properties.

JSON zu TypeScript

TypeScript-Schnittstellen und Typen aus JSON generieren

JSON-Eingabe

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TypeScript-Ausgabe

Root interface:

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Generate exact TypeScript types from real payloads

Hand-typing interfaces from an API response is error-prone — you forget a field, get a type wrong, miss a nested array. Generating TypeScript directly from a sample payload produces named interfaces, typed arrays, and nested types that match the data exactly, ready to paste into your code.

Use the converter when you need to

Type a new API response

Drop a sample response in, get back interfaces you can import without writing a single property by hand.

Catch shape changes during integration

Regenerate types when the API response shape evolves and let TypeScript surface every downstream break.

Type third-party SDK responses without docs

When an SDK lacks types, generate them from a real response and gain autocomplete instantly.

How to generate TypeScript from JSON

1
Paste a sample JSON document into the editor.
2
Optionally rename the root type to match your domain.
3
Copy the generated interfaces into your codebase or a shared types package.

Keep going

Generate types in other languages

Produce Python, Java, Go, C#, Kotlin, Rust, or Swift types from the same JSON sample.

Generate a JSON Schema

Create a runtime contract you can validate against, in addition to compile-time types.

Mock data for these types

Generate matching fake data to build UI before the real backend exists.

Format the source first

Clean up the sample payload so the generated type names follow consistent casing.

Common JSON-to-TypeScript workflows

Bootstrap a typed API client

Generate interfaces from one real response and use them across every fetch call in your app.

Type a webhook payload

Drop a sample webhook event in and get types your handler can import on day one.

Validate model output shape at compile time

Generate interfaces for structured AI output so the compiler flags missing or renamed fields.

Häufig gestellte Fragen

Du fügst ein JSON-Objekt ein, und das Tool analysiert Struktur, Datentypen und Verschachtelungen, um daraus TypeScript-Interfaces zu generieren. Arrays werden anhand ihres Inhalts typisiert, und verschachtelte Objekte bekommen eigene, benannte Interfaces.

Die Interfaces werden aus den Beispieldaten abgeleitet: Ist ein Feld im Sample vorhanden, wird es als required generiert. Optionale Felder musst du nachträglich prüfen und bei Bedarf manuell mit dem ?-Modifier markieren.

Ja — das ist einer der häufigsten Anwendungsfälle. Kopiere eine JSON-Response aus deiner API, füge sie ein, und du bekommst sofort TypeScript-Interfaces für deinen Frontend-Code. Das spart besonders bei REST APIs viel Zeit.

Strings werden zu string, Zahlen zu number, Booleans zu boolean, null zu null, Arrays zu typisierten Arrays (z. B. string[]), und Objekte zu benannten Interfaces mit ihren Properties.