JSON to TypeScript — Generate Interfaces Online

Paste JSON and get TypeScript interface or type definitions. Choose root name, interface vs type alias, and optional properties — all processing stays in your browser.

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JSON to TypeScript — generate interfaces from samples
Turn API fixtures and config exports into compilable-looking TypeScript definitions. Distinct from JSON formatter (whitespace) and validator (syntax).

Developer notes

Root must be a JSON object or array. Optional properties add `?` to fields — review before publishing shared types. Type aliases vs interfaces follow your selected option. Validate source JSON first when payloads are untrusted.

When teams use JSON → TypeScript

Bootstrap SDK types from example API responses. Document config shapes for Rust/Python teams sharing JSON fixtures. Quick prototypes before adopting schema-first tooling.

Examples

User object

Sample JSON

{ "user": { "id": 42, "name": "Ada Lovelace", "active": true }, "address": { "street": "10 Downing St", "city": "London", "postcode": "SW1A 2AA" } }

Generated TypeScript

interface RootObject { user: User; address: Address; } interface Address { street: string; city: string; postcode: string; } interface User { id: number; name: string; active: boolean; }

Nested payload

Sample JSON

{ "user": { "email": "[email protected]" } }

Generated TypeScript

Nested `user` object with `email: string` field.

Navigate related JSON tools

Browse the JSON tools hub. Validate with the JSON validator, prettify via the JSON formatter, or repair broken syntax with JSON repair.

JSON to TypeScript FAQ

Type generation, not validation

Does this validate JSON?

Invalid JSON errors before generation — use the JSON validator for detailed diagnostics.

Union types for mixed arrays?

json-to-ts infers unions when array items differ — review output manually.

Server uploads?

Never — conversion runs locally after dynamic import.

JSON Tools

Validate, format, diff and explore JSON payloads — complementary to minifiers and converters.

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