How to use this tool
- Paste JSON, upload a local file, or load a CORS-enabled public URL.
- Choose indentation and run Generate TypeScript.
- Review the result, then copy it or download it with the correct file type.
Private by default
JSON to TypeScript Type Generator
Turn representative API payloads and fixtures into a readable JsonSample type without sending data to a server.
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AuditableDocumented semantics
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Category
JSON to TypeScript: How to use this tool
Generate a deterministic TypeScript type alias from any valid JSON sample, including nested objects and mixed arrays.
Turn representative API payloads and fixtures into a readable JsonSample type without sending data to a server.
Open guide and examples
Example to try
Input JSON
{
"user": {
"id": 101,
"display-name": "Ada",
"active": true
},
"roles": ["admin", "editor"],
"metadata": null
}Result
export type JsonSample = {
metadata: null;
roles: Array<string>;
user: {
active: boolean;
"display-name": string;
id: number;
};
};
Learn
Frequently asked questions
Does this tool upload my JSON?
No. The transformation runs in your browser. URL import contacts only the address you explicitly enter.
What happens when the JSON is invalid?
The editor marks the likely location and keeps stale output out of the result pane.
What does JSON to TypeScript produce?
It emits an exported JsonSample type with quoted unsafe property names, recursively inferred fields, and deterministic key ordering.
What limitation applies to JSON to TypeScript?
A sample cannot reveal optional fields or domain rules. Empty arrays become unknown[] and all JSON numbers become TypeScript number.