Free JSON to TypeScript

JSON to TypeScript (2026) ✨

Generate TypeScript types from JSON. Free, no signup, runs in browser. By Folioify.

Fast- convert in seconds

Private- local processing

No Signup- free forever

JSON to TypeScript Tool 🧰

Paste your input below and the output will update automatically.

TL;DR ⚡

Turn JSON samples into TypeScript types so API payloads, config objects, and mock data become type-safe faster.

Example Input

{
  "id": 42,
  "name": "Folioify",
  "tags": ["tools", "converter"],
  "meta": { "version": 1 }
}

Expected Output

interface Root {
  id: number;
  name: string;
  tags: string[];
  meta: {
    version: number;
  };
}

Core Information 📌

Pricing

Free — no registration required.

Data Handling

Client-side only — runs in your browser.

Output

Instant conversion with clean results.

Target Users

Developers, designers, and creators.

What is JSON to TypeScript? 🧭

JSON to TypeScript infers structural types from JSON input and outputs interfaces or type aliases you can drop into frontend or backend TypeScript projects.

What can it do? ✅

Infer strings, numbers, booleans, arrays, and nested objects.
Generate TypeScript-friendly property names and nested shapes.
Use real API responses or config snippets as input.
Produce copy-ready types for interfaces and type aliases.

How JSON to TypeScript works (Step-by-Step) 🪄

Step 1: Paste valid JSON into the editor.
Step 2: The converter reads the value shape and maps fields to TypeScript types.
Step 3: Copy the generated interface or type alias into your project.

Common Errors

Invalid JSON syntax stops type generation.
A single sample may miss optional fields present in production data.
Mixed-type arrays can infer broad union types.

Limitations

Generated types should be reviewed before production use.
Null-only samples may not reveal the intended non-null type.
Business rules and runtime validation are not inferred.

Free vs Paid 💸

This tool is 100% free with no usage limits or account required. You can use it for quick conversions without subscriptions or payments.

Official vs Third-Party 🧪

Folioify provides this as a third-party utility. It does not replace official tools, but offers a fast, accessible alternative for everyday workflows.

Use Cases 💡

Create API response types from example payloads.
Type frontend state objects during refactors.
Document JSON configuration with strict TypeScript models.
Bootstrap types before OpenAPI or schema generation.

Frequently Asked Questions ❓

Does it support nested JSON?

Yes. Nested objects become nested TypeScript types with inferred property shapes.

Can it handle optional fields?

Optional fields are inferred from the sample you provide. Use representative payloads with and without optional keys for better results.

Is my JSON uploaded to a server?

No. Conversion runs locally in your browser for privacy.

Data Sources & Disclaimer 📎

This tool is provided for educational and productivity purposes. Output accuracy depends on input quality. It uses json_typegen_wasm as a processing library.

Last updated: July 4, 2026. This page is maintained regularly so tool details, examples, and FAQs stay current for developers and AI search systems.