JSON to TypeScript / Zod

When working with APIs, configuration files, or any JSON data in a TypeScript project, you need type definitions that describe the shape of your data. Writing these interfaces by hand is tedious and error-prone, especially for deeply nested structures with optional fields and mixed-type arrays. A JSON-to-TypeScript converter automates this by analyzing sample JSON data and generating accurate type definitions instantly.

This tool generates two output formats: TypeScript interfaces and Zod validation schemas. TypeScript interfaces provide compile-time type checking, while Zod schemas give you runtime validation — ensuring data from APIs or user input actually matches your expected types. Both are essential for building type-safe applications.

The converter handles nested objects (generating separate interfaces for each level), arrays with consistent or mixed element types, optional fields (detected by comparing multiple array elements), and primitive types (string, number, boolean, null). It generates clean, ready-to-use code with proper PascalCase naming. All processing happens in your browser — your data never leaves your machine.

1. Paste your JSON — Enter any valid JSON data in the left panel. Click "Load Example" for a comprehensive sample with nested objects and arrays.
2. Choose your output format — Select "TypeScript" for interface definitions or "Zod" for validation schemas with runtime type checking.
3. View generated types — Types are generated in real-time as you edit the JSON. Nested objects produce separate named interfaces.
4. Copy the code — Click "Copy" to copy the generated TypeScript or Zod code to your clipboard, ready to paste into your project.

• TypeScript interfaces — Generates clean, exported interfaces with proper PascalCase naming and nested type definitions.
• Zod schema generation — Produces complete Zod validation schemas with inferred TypeScript types, ready for runtime validation.
• Nested object handling — Automatically creates separate interfaces for each nested object level, keeping your type definitions clean and reusable.
• Optional field detection — When converting arrays of objects, fields that appear in some items but not others are marked as optional (?).
• Union type inference — Mixed-type arrays and fields generate proper union types (e.g., string | number).
• Syntax highlighting — Generated code is color-highlighted for keywords, types, and values for easy reading.
• 100% client-side — Your JSON data never leaves your browser. No server, no uploads, no tracking.

• API response typing — Paste a sample API response to instantly generate TypeScript interfaces for your HTTP client (fetch, axios, etc.).
• Database schema types — Generate types from JSON database documents (MongoDB, DynamoDB, Firestore) for use in your application code.
• Runtime validation — Generate Zod schemas to validate incoming API data, form submissions, or webhook payloads at runtime.
• Config file types — Create type definitions for JSON configuration files to get autocomplete and type checking in your IDE.
• Rapid prototyping — Quickly generate types when exploring a new API, then refine them as you learn more about the data shape.