Free online JSON to TypeScript interface generator. Paste JSON and instantly generate TypeScript interfaces and types with automatic type inference, nested object support, and nullable field detection. 100% browser-based — your data never leaves your device.
100% browser-based — your data never leaves your device
Convert JSON to TypeScript interfaces instantly. Generate typed interfaces from JSON samples for type-safe development.
Copy your JSON data and paste it into the input textarea above.
Toggle nullable field detection and nested object depth settings as needed.
Click Generate, then copy the TypeScript interfaces or download the .ts file.
Drop a file here or click to browse
Ctrl+Enter to generate
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JSON to TypeScript is a free online json tool that convert json to typescript interfaces instantly. generate typed interfaces from json samples for type-safe development. It works entirely in your browser — no downloads, no installations, and no server uploads required. backend developers, frontend engineers, DevOps engineers use JSON to TypeScript when they need a fast, privacy-respecting way to process json data without installing additional software. It supports capabilities such as type inference, nullable fields, nested objects. Additional features include local processing. Common use cases include generating typescript interfaces from api response json for type-safe data fetching, creating type definitions from sample configuration files and data structures, rapid prototyping of type-safe data models from mock json data. All processing happens locally using modern browser APIs, which means your data never leaves your device. This makes JSON to TypeScript ideal for working with sensitive data, proprietary code, or any situation where privacy matters.
JSON to TypeScript Interface Generator is a free online json tool that helps you convert json to typescript interfaces instantly. generate typed interfaces from json samples for type-safe development. Key capabilities include type inference, nullable fields, nested objects. All processing is done locally in your browser — no data is uploaded, stored, or shared with any server. There are no sign-ups, no file size limits, and no hidden charges. It is commonly used to generating typescript interfaces from api response json for type-safe data fetching.
Copy your JSON data and paste it into the input textarea above.
Toggle nullable field detection and nested object depth settings as needed.
Click Generate, then copy the TypeScript interfaces or download the .ts file.
| Category | Details |
|---|---|
| Input Limits | Maximum file size: Browser memory bound (~2 GB) |
| Nesting depth: Unlimited (browser stack limit) | |
| Supported Formats | JSON, JSONC (with comments), JSON5 (extended syntax) |
| Browser Engine |
|
All operations run entirely in your browser using built-in JSON APIs. No server uploads, no data storage, and no third-party requests.
JSON to TypeScript is ideal when you need to generating typescript interfaces from api response json for type-safe data fetching without installing software or uploading data to a server. Since everything runs in your browser, there is no setup time and no risk of your data being stored on external servers. For for persistent editing environments with linting, consider using VS Code with JSON extension. For for server-side JSON processing in scripts, jq (command-line) may be a better fit. JSON to TypeScript fills the gap between heavyweight desktop tools and insecure online services that require uploading your data.
No. JSON to TypeScript processes everything entirely in your browser using JavaScript. Nothing you type, paste, or upload is ever transmitted to any server. Your data never leaves your device.
The generator creates interfaces with proper type annotations, optional properties (?), readonly for nested references, and export statements for modular usage.
Nested objects are extracted into separate named interfaces that reference each other. This keeps the generated code clean and idiomatic for TypeScript.
Automatically detects string, number, boolean, array, null, and nested object types from your JSON.
Optionally mark fields as nullable (union with null) when the JSON contains null values.
Recursively generates interfaces for deeply nested JSON structures with proper imports.
All conversion happens in your browser — your JSON never leaves your device.
JSON to TypeScript Interface Generator is useful in a variety of scenarios across different workflows:
Generating TypeScript interfaces from API response JSON for type-safe data fetching
Creating type definitions from sample configuration files and data structures
Rapid prototyping of type-safe data models from mock JSON data
Include all possible fields and edge cases (null values, empty arrays) in your sample JSON to generate the most complete interfaces.
Enable nullable field detection when working with real API responses — fields that can be null are common and should be typed correctly.
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