JSON to TypeScript Generator

Convert JSON payloads into strongly-typed TypeScript interfaces locally.

JSON to TypeScript Converter

Paste JSON Payload0 characters

Generated TypeScript Interfaces

Waiting for valid JSON input...

How to Use

Paste JSON

Input your raw JSON data or API payload.

Convert

The generator recursively extracts keys and builds interface declarations.

Copy Interface

Copy the compiled TypeScript declarations to your clipboard.

Real-World Examples & Use Cases

Frontend API Integration

When consuming new endpoints from a REST API, developers need to ensure type safety for their HTTP client responses. Rather than manually typing out hundreds of fields for complex payloads, pasting the raw JSON response here generates complete, structured TypeScript interfaces in seconds.

State Management Store Typing

Modern state libraries like Redux, Pinia, or Zustand require strict typing for application stores. If your initial store data or state payload is modeled as a JSON object, this tool generates the correct interface hierarchies to prevent runtime bugs.

Config & Settings File Mapping

Projects often store complex configurations in JSON format (e.g., dashboard themes or tool lists). To safely read and edit these settings within TypeScript codebases, developers convert the config schema into a Type interface to get full IDE autocomplete and compile-time verification.

How It Works

JSON to TypeScript Type-Mapping and Parser Logic: The converter uses a recursive parser that traverses the parsed JSON object hierarchy: 1. Primitive Detection: Inspects the JavaScript typeof value: - string -> string - number -> number - boolean -> boolean - null / undefined -> any or null 2. Object Analysis: If the value is an object (and not null or an array), the generator recursively maps each key to its corresponding type. It extracts child objects and generates distinct sub-interfaces (named based on the key capitalized) to maintain code cleanliness instead of inline anonymous types. 3. Array Normalization: When encountering an array, the parser inspects the items: - If empty: defaults to any[] - If homogenous (e.g., all numbers): maps to number[] - If mixed (e.g., strings and numbers): maps to (string | number)[] - If array of objects: merges their properties into a single interface structure to handle optional/nullable fields cleanly across the array items.

Frequently Asked Questions

Does this generator support nested JSON objects?▼

Yes. The parser recursively traverses nested structures. When it encounters a nested object, it extracts it into its own standalone interface (e.g., UserDetails) and maps the parent key to that interface name, keeping your code modular and readable.

How are duplicate key names handled across different levels?▼

To prevent namespace collisions, the parser appends numerical suffixes or parent names to sub-interfaces if a name conflict is detected. This ensures that every interface in the output has a unique identifier.

Does this tool support JSON arrays?▼

Yes. If a JSON array is homogenous, it converts to `Type[]`. If the array contains objects with varying keys, the parser does a union merge, marking non-common fields as optional (using `?:`) so that the resulting interface safely represents any item in the dataset.

Why does this tool run client-side?▼

API payloads often contain sensitive user data, PII, or internal database architectures. Doing the conversion entirely inside your browser ensures that your raw JSON payloads are never uploaded, logged, or intercepted by a remote server.

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