MetoolzyJSON to TypeScript
Type Inference
Automatically infers TypeScript types from JSON values.
Nested Objects
Generates separate interfaces for nested objects.
Array Support
Handles arrays, arrays of objects, and mixed-type arrays.
Client-side
All processing in your browser. No data uploaded.
About JSON to TypeScript
The JSON to TypeScript Converter instantly transforms any JSON object or array into strongly-typed TypeScript interfaces or type aliases. Rather than writing type definitions by hand — a tedious and error-prone process — this tool analyzes your JSON structure and infers the correct TypeScript types for every field automatically. When you work with REST APIs, GraphQL responses, or configuration files, you often receive raw JSON payloads. Manually maintaining type definitions that match evolving API schemas leads to drift and bugs. This converter bridges that gap: paste your JSON response, adjust options like the root interface name, optional properties, or whether to use `type` vs `interface`, and get production-ready TypeScript in seconds. The tool handles nested objects (generating separate named interfaces for each), arrays (including arrays of objects and mixed-type arrays), primitive types (string, number, boolean), and null values. All conversion runs entirely in your browser — your data never leaves your machine, making it safe for proprietary API schemas and internal data models. Whether you are bootstrapping a new TypeScript project or retrofitting types onto an existing codebase, this tool dramatically reduces boilerplate and helps you ship type-safe code faster.
How to Use JSON to TypeScript
- Paste your JSON object or array into the left input panel, or click "Load Sample" to try an example.
- Set your preferred root interface name in the "Root name" field (default is "Root").
- Toggle options as needed: use "type" instead of "interface", mark all properties as optional, or add the "export" keyword.
- The TypeScript output updates in real time in the right panel as you type or change options.
- Review the generated interfaces — nested objects produce additional named interfaces above the root.
- Click "Copy" to copy the output to your clipboard and paste it directly into your TypeScript file.
Frequently Asked Questions
What TypeScript types does this tool generate?
The converter infers string, number, boolean, null, arrays (including typed arrays like string[] or object arrays), and nested object interfaces. Unknown types fall back to the "unknown" TypeScript type.
Can I convert a JSON array instead of a single object?
Yes. If you paste a JSON array whose first element is an object, the tool generates an interface for that element shape. If the array contains primitives, it generates a simple type alias like "type Root = string[]".
What is the difference between "interface" and "type" output?
Both are valid TypeScript. Interfaces are generally preferred for object shapes and support declaration merging. Type aliases (using the "type" keyword) are more flexible and can represent unions and other complex types. Toggle the checkbox to choose your preferred style.
Does this handle keys with special characters or spaces?
Yes. Property keys that are not valid JavaScript identifiers are automatically wrapped in double quotes in the output (e.g., "my-key": string).
Is my data sent to a server?
No. All processing happens entirely in your browser using JavaScript. No data is uploaded or stored anywhere.
What should I do if a JSON property has different types in different objects?
The tool infers types from the first item it encounters. For mixed arrays, it creates a union type like (string | number)[]. For more precise control over optional or union fields, you can edit the generated output manually after copying.
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The Ultimate JSON to TypeScript
JSON to TypeScript is a powerful, free online tool designed to simplify your digital workflow. Convert JSON to TypeScript interfaces and types.
In today's fast-paced digital world, efficiency is key. Whether you're a developer, designer, or digital marketer, finding reliable utilities is crucial. With our JSON to TypeScript, you can get things done instantly right in your browser, with absolutely no signup required.
Why Use Our JSON to TypeScript?
Our tool is built with performance and privacy in mind. All processing is incredibly fast, ensuring you don't waste any time.
- 100% Free: No hidden fees or premium paywalls.
- No Installation: Works instantly in any modern web browser.
- Privacy First: We respect your data. Most processing happens directly on your device.
- User-Friendly: A clean, intuitive interface that anyone can use without technical skills.
How it benefits your workflow
Integrating the JSON to TypeScript into your daily routine saves you valuable time. Instead of downloading bulky software or writing custom scripts, you can bookmark this page and solve your problem in just a few clicks.
Try it out today and experience the easiest way to handle your tasks!
Top 10 Free Tools Every Developer Needs
Boost your productivity instantly. Get our exclusive cheatsheet featuring the most essential web utilities you didn't know you needed, delivered straight to your inbox.
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