JSON to Elm

Convert JSON to Elm type.

This tool is designed to provide a seamless experience for developers by handling complex operations directly in your browser with maximum speed and security.

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JSON (JavaScript Object Notation) is a lightweight data-interchange format. It is easy for humans to read and write and easy for machines to parse and generate. It is the language of the web APIs.

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It converts JSON data into clean, idiomatic Elm type aliases and decoders, ensuring total type safety in your Elm applications. The tool intelligently identifies data types and creates the necessary boilerplate code for working with JSON, including support for nested objects, arrays, and custom types. It generates the explicit decoders required by Elm to handle external data, which can be a complex and repetitive task to write manually. This is an essential tool for Elm developers who want to quickly integrate REST APIs or external data sources while maintaining the language's strong guarantees against runtime exceptions and ensuring a clean visual hierarchy of data.

Input your JSON to generate Elm type aliases and JSON decoders/encoders. It handles nested structures by creating multiple types and corresponding decoders.

Elm is a purely functional language where JSON decoding is explicit and must be handled carefully. This tool simplifies this often difficult process by generating the decoders and encoders for you, reducing boilerplate code and significantly lowering the risk of runtime errors in your frontend applications.

Example Input

{
  "id": 1,
  "name": "John Doe",
  "email": "john@example.com",
  "isActive": true,
  "tags": ["admin", "dev"],
  "profile": {
    "bio": "Software Engineer",
    "skills": ["Go", "React", "TypeScript"]
  }
}

Example Output

type alias User =
    { id : Int
    , name : String
    , email : String
    , isActive : Bool
    }

Decoder Complexity

Fix: Highly nested JSON can result in complex decoders. The tool breaks these down into smaller, manageable functions.

Does it support Elm 0.19?

Yes, the generated code is compatible with Elm 0.19 and later.

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