TypeScript Interface Generator
DeveloperGenerate TypeScript interfaces from JSON data. Speed up your development workflow.
What is This Tool?
A TypeScript interface generator creates TypeScript type definitions from JSON data, API responses, or manual configuration. Paste JSON to automatically generate matching interfaces with proper types, optional properties, and nested object/array handling — saving hours of manual type definition.
TypeScript interfaces define the shape of objects, providing autocompletion, type checking, and documentation. Manually typing interfaces for complex API responses is tedious and error-prone. This tool infers types from sample data, handling nested objects, arrays, union types, and nullable values.
Common Use Cases
API Integration
Generate TypeScript interfaces from API response samples to get full type safety for fetched data.
Data Modeling
Create type definitions for database models, form data, and application state from example data.
Code Generation
Automate interface generation in build pipelines from OpenAPI specs, GraphQL schemas, or JSON samples.
Migration to TypeScript
Generate interfaces from existing JavaScript data structures when migrating a codebase to TypeScript.
Frequently Asked Questions
Interface vs type alias?
Interfaces support extension (extends) and declaration merging. Type aliases support unions and intersections. For object shapes, interfaces are conventional; both work.
Are optional properties detected?
When analyzing multiple JSON samples, properties that appear in some but not all samples are marked as optional (?).
Are nested objects typed?
Yes. Nested objects generate separate named interfaces. Arrays are typed based on their element types, including union types for mixed arrays.