JSON to TypeScript Interface Generator
Paste raw JSON API responses or database objects and instantly generate clean, strongly-typed TypeScript interfaces with support for nested structures, arrays, and optional fields.
📘 TypeScript Interface Generation Guide
Nested Interface Extraction
Deconstructs deeply nested JSON objects into modular, re-usable PascalCase TypeScript interfaces, avoiding unreadable inline type declarations.
Array Schema Merging & Optionality
Scans all objects across an array rather than just the first item. If a property appears in some objects but is omitted in others, it is correctly inferred with the optional modifier (key?: type).
Clean Quoted Identifiers
Automatically wraps property names with dashes, special characters, or spaces in quotes (e.g. "user-id": string) while preserving unquoted identifiers for standard keys.
Null & Primitive Inference
Accurately identifies strings, booleans, floating-point numbers, and handles null values safely with union types (any | null) rather than blindly defaulting to any.
Empty Container Handling
Gracefully falls back to any[] for empty arrays and Record<string, any> for empty objects without throwing compiler errors.
1-Click Codebase Integration
Export clean, production-ready code you can paste directly into your Next.js, React, Node.js, or backend TypeScript projects.
❓ Frequently Asked Questions
Why should I use TypeScript interfaces over 'type' aliases for API responses?
In TypeScript, interfaces are generally preferred for object models because they generate clearer IDE hover tooltips, support declaration merging, and provide slightly better compiler caching performance compared to complex intersected type aliases.
How does the generator handle inconsistent array items?
When parsing an array of objects, our engine compares keys across all items in the array. Any key that does not appear in 100% of the sample objects is marked with an optional modifier (key?: type) so your TypeScript code won't produce runtime undefined errors.
Does this tool work with strict TypeScript settings?
Yes. The generated code strictly defines every nested interface and avoids implicit any wherever sample data exists. You can compile it under strict: true and noImplicitAny: true without warnings.