Can I generate type aliases instead of interfaces?

Yes. You can switch between 'interface' and 'type' declarations with a single click in the options panel.

How are null and optional values handled?

Fields with null values are typed as 'unknown | null', allowing you to safely refine types in your application codebase.

Does my JSON get sent to an external server?

Never. All parsing and recursive AST type generation executes entirely within your browser runtime.

All Developer Tools

TypeScript Type Generator

JSON to TypeScript Converter

Generate clean, recursive, strongly typed TypeScript interfaces or type aliases from any JSON payload.

100% In-Browser Client-Side — Zero Server Uploads

Root Name:

export

Successfully generated TypeScript definitions

399 B15 keys

JSON Input

Upload

21 lines•399 chars

399 B

Generated TypeScript Definitions (.ts)

export interface UserProfile {
  userId: number;
  username: string;
  email: string;
  isVerified: boolean;
  profile: UserProfile_Profile;
  roles: string[];
  projects: UserProfile_Project[];
}

export interface UserProfile_Profile {
  displayName: string;
  avatarUrl: string;
  age: number;
  bio: unknown | null;
}

export interface UserProfile_Project {
  id: string;
  name: string;
  stars: number;
  isPublic: boolean;
}

23 lines•430 chars

430 B

Why Generate TypeScript from JSON with PicoFix?

Recursive type safety, modular interface decomposition, and zero server exposure.

Recursive Nested Models

Rather than dumping an unwieldy inline object literal, PicoFix extracts nested objects into distinct PascalCase interfaces (e.g. UserProfile, UserProfile_Address, GeoLocation) for clean, maintainable TypeScript architectures.

Interfaces & Type Aliases

Switch effortlessly between interface declarations and type alias definitions with a single click. Configure optional export prefixes to match your codebase conventions.

Array & Null Resilience

Handles homogeneous arrays, mixed arrays with union types, empty arrays (any[]), and nullable fields without crashing or emitting invalid syntax.

JSON to TypeScript FAQs

Helpful answers to common image compression questions.

PicoFix recursively inspects nested objects and extracts them into separate, cleanly named PascalCase interfaces so your TypeScript definitions remain modular and readable.

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