JSON to TypeScript.
Generate clean TypeScript interfaces (or type aliases) from any JSON sample — with named nested types, optional-field detection, and readonly support. Instant and 100% private, in your browser.
No signup · No uploads · No file-size cap
TypeScript
// Paste JSON and press “Generate types”.Convert JSON to TypeScript online
A JSON to TypeScript converter turns sample JSON into TypeScript interfaces or type aliases. Paste an API response, webhook payload, config object, or mock JSON above and generate clean types with nested names, optional fields, readonly support, and custom root naming.
Generate interfaces from realistic JSON samples
The best JSON to TypeScript interface output comes from realistic examples. Arrays help detect optional fields, nested objects become named shapes, and null values can be represented explicitly so your frontend, backend, or SDK code gets safer autocomplete.
Why use this JSON to TS converter?
It is instant, private, and focused on practical TypeScript output. Use
it when wiring up a new API response, documenting sample data, or
replacing loose any types. Need a validation contract too?
Try the JSON Schema Generator or read
how to convert JSON to TypeScript.
FAQ
JSON to TypeScript, answered.
How do I convert JSON to TypeScript online? +
Paste a JSON sample into the converter, choose interface or type alias output, set a root type name, and generate. The tool infers TypeScript types from objects, arrays, strings, numbers, booleans, nulls, and nested data.
Can it generate TypeScript interfaces from JSON? +
Yes. You can generate TypeScript interfaces from JSON, including named nested interfaces. This is useful for API responses, webhook payloads, mock data, and config objects.
Can I generate type aliases instead of interfaces? +
Yes. The converter supports both TypeScript interfaces and type aliases, so you can match the style used in your codebase.
How does it detect optional fields? +
When your sample is an array of objects, the tool compares keys across rows. Fields that appear in some objects but not others can be marked optional with the ? modifier.
How are null values handled? +
Null values can be represented as union types such as string | null, or handled with the null-as-optional option depending on how your API represents missing data.
Is my JSON uploaded when generating TypeScript? +
No. JSON to TypeScript conversion is 100% client-side. Your sample is parsed and converted locally in your browser and is never uploaded or stored.