TypeScript Type Generator from JSON
Paste a JSON sample, get TypeScript interface definitions. Nested objects automatically become named child interfaces. Arrays infer item types with union when items vary. Null / undefined fields marked optional.
interface Root {
id: number;
name: string;
email: string;
active: boolean;
address: Address;
projects: Projects[];
}
interface Projects {
title: string;
stars: number;
tags: string[];
}
interface Address {
city: string;
country: string;
}
What powers the TypeScript Type Generator
Recursive interface generation for nested objects
Array item type inference with unions
Optional (?) marker for null / undefined fields
Configurable root type name
Camelcased child type names
Instant
Why the TypeScript Type Generator is different
Browser-native
The TypeScript Type Generator runs entirely in your browser. Input is processed locally — never uploaded, never logged, never cached anywhere outside your device.
No artificial limits
No daily quotas, no character ceilings, no "upgrade for more" walls. Every feature is the complete feature — the same on the first use as the thousandth.
Production-grade quality
Built to the same engineering bar as paid SaaS tools — accurate algorithms, audited logic, responsive design and accessibility-tested interactions.
Common use contexts
- API integration — generate types from a sample response
- Migrating JavaScript codebase to TypeScript
- Generating Strapi / Sanity / Contentful response types
- Quick types for prototyping
Private and secure
Zero upload
All processing happens in your browser. Input is never transmitted, logged or cached.
Works offline
Once the page loads, the tool runs without an internet connection. No network calls happen during use.
No tracking
No accounts, no cookies for tool state. Only aggregate analytics count visits at the page level.