JSON to TypeScript generator

Generate conservative TypeScript types from JSON examples locally in your browser.

Runs locally in your browser. Payloads, schemas, expressions, and generated output stay on your device.

Root type name

JSON input

JSON

{
  "account": {
    "id": "acc_123",
    "name": "Acme API",
    "active": true
  },
  "events": [
    { "type": "created", "attempt": 1 },
    { "type": "updated", "attempt": 2, "metadata": { "source": "web" } }
  ]
}

TypeScript output

TypeScript

Common uses

Bootstrap API response types from real example payloads.
Turn JSON examples into code-facing contracts before refining them by hand.
Create fixture types that preserve optional fields from repeated array objects.

Details

Does type generation upload my JSON?

No. TypeScript generation parses and infers types in your browser through the local JSON worker.

How opinionated are the generated types?

They stay conservative: strings, numbers, booleans, nulls, arrays, nested objects, unions for mixed values, and optional keys when array examples omit a field.

Private by default

The current tool runs in your browser. Payloads, schemas, expressions, and generated output are not sent to jsonpark.com, Supabase, Turnstile, or analytics.