JSON to TypeScript
Paste JSON, get clean TypeScript types instantly.
export type Root = {
id: number
name: string
email: string
active: boolean
score: number
tags: string[]
createdAt: string
address: {
city: string
country: string
zip: string
}
metadata: {
owner: unknown
plan: string
}
};
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Open toolWhy convert JSON to TypeScript?
Modern frontend and backend codebases lean on TypeScript for type safety, and most integrations — REST APIs, third-party webhooks, configuration files — speak JSON. Hand-typing interfaces for each payload is slow, error prone and drifts out of sync the moment the API response changes. Converting JSON to TypeScript types automatically turns a response shape into a compile-time contract: the moment a field is renamed, removed or its type changes, your editor and your CI pipeline catch it before your users do.
StackPulse's JSON to TypeScript converter accepts any valid JSON — objects, arrays, deeply nested payloads, arrays of mixed primitives — and generates a clean, strongly typed declaration with two-space or four-space indentation, in either type or interface style. Helpers like the null union, uniform arrays versus mixed unions, and quoted property names for unusual keys are handled automatically.
Because the conversion is 100% client-side, sensitive payloads — customer records, internal API responses, production data dumps — are processed locally and never leave the browser. There is no upload, no queue and no processing server, which is also why the result is effectively instantaneous and works even on flaky or offline network connections. The generated declarations are self-contained export type or export interface definitions that drop straight into your codebase.
Common use cases
How to convert JSON to TypeScript
- Paste a JSON payload, or click Sample to load a realistic example object.
- Choose type or interface output, plus the indentation width you prefer.
- Click Generate — or press Ctrl / ⌘ + Enter — to build the declaration.
- Review the nested interfaces: every object becomes its own named type.
- Copy the result into your types.ts file or download it for later reference.
Test cases
Input · {"id":1,"name":"Alice","role":"admin","tags":["react","api"]}
interface Root with id: number, name: string, role: string and tags: string[].
Input · {"ok":true,"data":{"items":[{"id":1,"price":9.99},null]}}
Nested Data interface with items: (Item | null)[] — union type for mixed arrays.
Frequently asked questions
Do you send my JSON to a server?
No. The entire conversion happens with a JSON parser and type generator running inside your browser tab. Your input is never transmitted and never stored.
What happens when keys are not valid TypeScript identifiers?
Keys that contain spaces, dashes or reserved words are automatically wrapped in quotes (e.g. "payment-status"), so the generated types always compile.
Which JSON values are supported?
Every JSON value: objects, arrays, strings, numbers, booleans and null. Homogeneous arrays become typed arrays; mixed arrays become unions; empty arrays become unknown[].