How do I convert JSON to a TypeScript interface?

Paste your JSON in the left editor and the TypeScript interface appears instantly on the right. The tool infers all field types including nested objects, arrays, strings, numbers, and booleans.

How are nested objects handled?

Each nested object becomes its own named interface. The name is derived from the parent key (converted to PascalCase). The parent interface references the child by name.

All tools JSON Schema Gen JSON → Excel AI Schema Masker

🔷

JSON to TypeScript Types Generator

Paste any JSON and instantly get TypeScript interfaces, type aliases, or Zod schemas. Handles nested objects, arrays, null values, and optional fields — 100% in-browser.

100% in-browserInterface · Type · ZodNested objectsNo signup

Samples:

data.json

types.ts

TypeScript types will appear here

Paste JSON on the left or load a sample

Output

Root name

Optional nullsSemicolonsExport all

You might also need

Browse all tools

JSON Schema GenGenerate JSON Schema JSON → ExcelExport JSON to Excel AI Schema MaskerMask sensitive data fields JSON FormatterBeautify & format JSON JSON BeautifierIndent & prettify JSON All tools

Stop Writing TypeScript Types by Hand

Every time you add a new API endpoint or change a response shape, you update the TypeScript interfaces by hand — copy the JSON from the browser network tab, mentally map each field to a type, handle nested objects, figure out what is optional, and hope you did not miss anything. It is the most repetitive part of front-end development.

Paste any JSON — user objects, API responses, config files, database records — and get immediately correct interface, type, or Zod definitions. Nested objects become separate named interfaces. Arrays are correctly typed as string[], User[], or union types.null values become optional fields. Copy and paste the result into your codebase.

How it works

Paste JSON, Get Types in One Step

Paste your JSON

Paste any valid JSON object or array into the left editor. Use a sample preset to try it instantly.

Pick your output format

Choose interface (default), type alias, or Zod schema. Set the root interface name and toggle options like "export all" and "optional nulls".

Copy and use

The TypeScript output updates in real-time. Click Copy to grab it and paste it straight into your project.

Use cases

When Developers Use a JSON to TypeScript Generator

🔗

API Integration

Copy a JSON response from your browser DevTools network tab and instantly get the TypeScript interface for the API data.

🗃️

Database Schema Typing

Take a sample record from your database and generate TypeScript types for your ORM or data access layer.

📦

Third-party SDK Types

When a library ships without TypeScript types, paste its JSON payload format to generate your own type declarations.

🤖

AI Response Typing

Generate TypeScript interfaces for ChatGPT, Claude, or Gemini API JSON responses before integrating them into your app.

⚙️

Config File Types

Create typed configuration objects for app settings, feature flags, or environment variable schemas.

🧪

Test Fixture Types

Generate types from test fixture JSON files to ensure your mock data matches your production interface shapes.

FAQ

Frequently Asked Questions

1How do I convert JSON to TypeScript types?

Paste your JSON in the left editor — TypeScript interfaces appear instantly on the right. The tool infers all types including nested objects, arrays, strings, numbers, and booleans. Click Copy to use the result in your project.

2Why does TypeScript not catch bad API response shapes at runtime?

TypeScript types are erased at compile time — they do not validate data at runtime. JSON.parse() returns any, so even a perfectly typed interface gives no protection against an unexpected API shape. Generate a Zod schema here and call schema.parse(JSON.parse(responseText)) for runtime safety with TypeScript inference.

3How do I handle optional fields in TypeScript types?

Fields whose JSON value is null are generated as optional (field?: Type | null). Toggle "optional nulls" to control whether null produces optional or nullable fields. Manually add the ? operator to any other fields that should be optional.

4How do I generate TypeScript from an API response?

Open browser DevTools, go to the Network tab, find the API request, copy the response body, then paste it here. TypeScript interfaces are generated instantly — the fastest way to type API responses without writing them by hand.

5How do I convert nested JSON to TypeScript interfaces?

Paste your nested JSON and the tool generates a separate named interface for each nested object. Each nested object key becomes a PascalCase interface name referenced from the parent interface.

6Can this tool generate Zod schemas?

Yes. Switch to "Zod" in the output options to get a z.object() schema with correct z.string(), z.number(), z.boolean(), z.null(), and z.array() types.

7How do I safely parse JSON in TypeScript?

Use Zod for safe parsing: generate a Zod schema with this tool, then call schema.parse(JSON.parse(text)). This validates the shape at runtime and gives you a fully typed result. JSON.parse() alone returns any, which bypasses TypeScript safety.

8How do I convert JSON to a TypeScript class?

Select "class" as the output format to generate a TypeScript class with typed properties. Classes support constructors and methods, suitable for domain models. For simple data transfer objects, interfaces are usually preferred.

9How do I keep my TypeScript types in sync when the API schema changes?

Re-paste the updated API response into this generator whenever the schema changes — regenerating takes seconds. For teams, use openapi-typescript (npx openapi-typescript schema.yaml --output types.ts) to generate types directly from an OpenAPI spec so they always match the documented contract.

10How do I generate types from a JSON Schema?

Use json-schema-to-typescript: npm install -g json-schema-to-typescript, then run json2ts schema.json > types.ts. This tool converts sample JSON directly without needing a formal schema.

11How do I use the generated TypeScript types in my project?

Copy the generated types, paste them into a .ts file in your project (e.g. types/api.ts), and import them: import type { UserResponse } from "./types/api". Use the interface to type API responses, function parameters, and state variables.

12How do I convert JSON to types in languages other than TypeScript?

Use Quicktype: quicktype --lang python, --lang go, --lang java, --lang rust, etc. For Python specifically, datamodel-code-generator generates Pydantic models from JSON or JSON Schema. For C#, use json2csharp.com or Quicktype.

Learn more

Developer Guides

📖TypeScript Best Practices 📖Typed API Clients in TypeScript 📖Zod Schema Validation Guide 📖JSON Schema vs TypeScript Types

Last updated: May 2026

Feedback for json_to_typescript

Tell us what's working, what's broken, or what you wish we built next — it directly shapes our roadmap.

You make the difference

Good feedback is gold — a rough edge you hit today could be smoother for everyone tomorrow.

Feature ideas often jump the queue when lots of you ask.
Bug reports with steps get fixed faster — paste URLs or examples if you can.
Name and email are optional; we won't use them for anything except replying if needed.

Stay Updated

Get the latest tool updates, new features, and developer tips delivered to your inbox.

What you'll get

Product updates & new tools
JSON, API & developer tips
Unsubscribe anytime — no hassle

Get in touch

Feature ideas, bugs, or a quick thanks — we read every message.

support@unblockdevs.com