Developer Tools
JSON to TypeScript Interface Generator — Free, No Upload
Convert any JSON object to TypeScript interfaces in one click. Nested objects become nested interfaces with correct names derived from JSON keys. Arrays are typed as T[]. No upload, no account — your JSON stays in your browser the entire time.
How to use this tool
- Paste your JSON into the input area and set a root interface name.
- Click Generate TypeScript to produce typed interfaces from all nested objects.
- Copy the interfaces and paste them directly into your TypeScript project.
Frequently Asked Questions
- Is my JSON sent to a server?
- No. The converter runs entirely in your browser using JSON.parse and a recursive type-inference function. Nothing is uploaded.
- How are nested objects handled?
- Each nested object becomes its own exported interface, named using the parent key in PascalCase. For example, a key "address" becomes an Address interface, and the parent interface references it by name.
- How are arrays typed?
- If an array is non-empty, the element type is inferred from the first item and expressed as T[]. If an array is empty, the type is unknown[].
- Does it handle all JSON value types?
- Yes — string, number, boolean, null, arrays, and nested objects are all supported. null is typed as null rather than any, which you can widen manually if needed.
JSON to TypeScript: Generate Interfaces Without Uploading Your Data (2026)
How to convert JSON to TypeScript interfaces in your browser. Most online converters send your payload to a server — this guide shows you a client-side alternative.