Are optional fields detected?

Not from a single sample — JSON doesn't mark optionality. Paste multiple payload variants and merge, or add ? manually where fields can be absent.

Is it safe to paste real API responses?

Here, yes — conversion is entirely client-side, so payloads never leave your device.

How to convert JSON to TypeScript interfaces

Hand-writing interfaces for a deep API response is tedious and error-prone. A generator infers the whole type tree from a sample payload in one paste.

Open JSON to TypeScript

Steps

Copy a real response payload from your API (DevTools → Network → Response).
Paste it into the JSON-to-TypeScript tool — interfaces generate instantly, nested objects become named sub-interfaces.
Copy the output into your codebase and refine: mark truly-optional fields with ?, widen enums, replace any[] from empty arrays.

What generated types can't know

A single sample can't reveal which fields are sometimes null or missing, whether a string is really a union of literals, or the element type of an empty array. Treat the output as a 90% head start: paste several different payloads and merge, then hand-tune the edge cases.

Since the tool runs client-side, pasting production API responses is safe — the data never leaves your browser.

Tools used in this guide

JSON to TypeScriptGenerate TS interfaces from JSON JSON FormatterBeautify and indent JSON JSON ValidatorValidate JSON and find errors