JSON to TypeScript Converter
Convert JSON to TypeScript interfaces and generate type definitions
JSON Input
TypeScript Output
What Is JSON to TypeScript?
You're building a React or Angular app, you've got a JSON API response in front of you, and you need to define a TypeScript interface for it. Writing it manually for a deeply nested response is tedious and error-prone — one wrong type and your editor stops catching bugs. This tool infers TypeScript interfaces directly from your JSON structure, so you can paste in the response and get ready-to-use type definitions in seconds.
Paste JSON, get TypeScript. The tool runs in your browser. Nothing is sent to a server. The output follows standard TypeScript syntax.
How to Use This Tool
Paste JSON
Paste your JSON into the left editor or upload a file. Use Sample for example data. The generator infers types from the structure. Use representative data that shows all the fields you care about.
Review the Interfaces
The right panel shows generated interfaces. Nested objects get their own interfaces. Arrays get typed as Type[]. Optional fields may use ? depending on the implementation.
Copy or Download
Use Copy or Download to get the TypeScript. Paste it into your project. You may need to adjust names, add generics, or fix optional fields. For validating the JSON first, use the JSON Validator.
Where JSON to TypeScript Helps
When integrating APIs, you often need types for the response payload. Pasting a sample response here gives you interfaces you can drop into your Angular, React, or Node project. Config files, webhook payloads, and database documents benefit from the same treatment. Manually writing interfaces for complex nested structures is error-prone; this tool infers the structure from your sample. For schema-based generation, use the JSON Schema Generator and tools like quicktype.
JSON to TypeScript Examples
Here is an example of generating TypeScript interfaces from a JSON object.
Example: Subscriber record
JSON input:
Generated TypeScript output:
Limitations
The generator infers from the sample. If a field can be string | number but your sample only has strings, the type will be string. If arrays can be empty, the element type might be unknown. Review and edit the output. For schema-based generation, use the JSON Schema Generator and a tool like quicktype.
Frequently Asked Questions
How do I generate TypeScript interfaces from JSON automatically?
Paste your JSON into this tool and it generates TypeScript interfaces based on the structure. Nested objects get their own interfaces, arrays get typed as Type[]. Copy the output into your Angular, React, or Node project.
What's the difference between TypeScript interface and type for JSON?
Both work well. interface is preferred when you need to extend or implement; type is better for union types and mapped types. For most API response shapes, either works — the generator outputs interface by default.
Is my data sent anywhere?
No. Everything runs in your browser — your JSON never leaves your machine. Safe to use with production API responses.
Can I generate types for other languages?
This tool outputs TypeScript only. The site has converters for C#, Java, Python, Go, and others.
What about optional fields and enums?
The generator infers types from your sample. Fields that could be optional won't be marked ? automatically — review the output and add ? where needed. For enums, if a field consistently uses specific string values, you can replace string with a union like "active" | "inactive".
Related Tools
For TypeScript, see typescriptlang.org and TypeScript objects. For JSON, see json.org and MDN JSON. For schema-to-code generation, see quicktype. For RFC 8259 (JSON spec).