Convert TypeScript
to JSON. Three ways,
one tool.
Generate mock JSON from an interface, get typed
JSON.stringify()
snippets, or convert your interface to a JSON Schema.
Choose the mode that matches your use case.
Each mode covers a different intent — choose the one that fits your use case.
Paste a TypeScript interface and get a valid JSON object with realistic example values. Useful when you need test fixtures, Storybook stories or API mock responses that match your type definitions exactly — without writing mock data by hand.
interface User {
id: number
name: string
active: boolean
}
{ "id": 1, "name": "string_1",
"active": true }
Get ready-to-use TypeScript code snippets for the most common JSON serialization patterns: basic stringify, typed wrapper functions, async fetch with typing, localStorage helpers and Node.js file write — all with correct TypeScript types.
const str = JSON.stringify(obj) const parsed: T = JSON.parse(str) await res.json() as T
Convert a TypeScript interface to a JSON Schema Draft-07 or 2020-12 document. TypeScript types are mapped to JSON Schema keywords: optional fields (?) are excluded from required, arrays get item types, and nested interfaces become $defs references.
interface User {
id: number
name?: string
}
{ "type": "object",
"required": ["id"],
"properties": {
"id": { "type": "number" },
"name": { "type": "string" }
}}
The four most common workflows where each mode applies.
Unit tests and Storybook stories need typed mock objects that match your interfaces exactly. Mode 1 generates them from the interface definition — no manual mock writing, no risk of type mismatch between the mock and the actual interface.
TypeScript's type system disappears at runtime — you need JSON.stringify() for network requests, storage and logging. Mode 2 gives you the correct typed serialization pattern for your specific use case: fetch, axios, localStorage, or Node.js file write.
TypeScript interfaces enforce types at compile time only. For runtime validation of API responses, form inputs or config files, you need a JSON Schema. Mode 3 converts your existing interfaces to a Draft-07 schema you can use with AJV, Fastify or Zod's z.fromJsonSchema().
OpenAPI 3.0 uses JSON Schema for request and response types. Converting your TypeScript interfaces to JSON Schema gives you the components/schemas section of your OpenAPI document — keeping your type definitions as the single source of truth between compile-time types and runtime validation.
TypeScript parsed with
regex. No compiler needed.
TypeScript interfaces are parsed with a field-level regex — no need to load the TypeScript compiler (4MB+). The parser extracts field names, types and optionality from the interface body, covering the most common patterns used in real-world TypeScript codebases.
The three output modes share the same parser and produce output that is immediately usable: mock data for tests, serialization patterns for production code, and JSON Schema for runtime validation — all from the same interface definition.