JSON to Elm Converter: Streamline Your Elm Development

Working with JSON in Elm can be repetitive and error-prone. Our JSON-to-Elm generator automatically converts JSON data into ready-to-use Elm types and decoders, saving time and reducing errors.

Why Developers Need a JSON-to-Elm Tool

Manually converting JSON to Elm types:

Is time-consuming
Introduces type mismatch errors
Requires boilerplate for nested JSON decoders
Slows down Elm app development

An automated generator ensures speed, accuracy, and maintainable code.

Key Features of JSON-to-Elm Generator

Automatic type and decoder generation
Supports nested JSON objects and arrays
Correctly infers types: Int, Float, String, Bool, List
Supports JSON from files or URLs
Copy or export .elm files ready for your project

How the JSON-to-Elm Generator Works

Step 1: Paste JSON

Insert your JSON in the left panel.

Step 2: Click Convert

Click the Convert button in the center.

Step 3: View Output

The generated Elm types and decoders appear on the right panel, ready to copy or export.

Example: Simple JSON Conversion

Input JSON:

{
  "id": 101,
  "name": "LangStop",
  "tags": ["json", "elm", "converter"]
}

Generated Elm Code:

type alias Root =
    { id : Int
    , name : String
    , tags : List String
    }
 
rootDecoder : Decoder Root
rootDecoder =
    map3 Root
        (field "id" int)
        (field "name" string)
        (field "tags" (list string))

Example: Nested JSON Conversion

Input JSON:

{
  "user": {
    "id": 1,
    "profile": {
      "age": 25,
      "email": "user@example.com"
    }
  }
}

Generated Elm Code:

type alias Profile =
    { age : Int
    , email : String
    }
 
profileDecoder : Decoder Profile
profileDecoder =
    map2 Profile
        (field "age" int)
        (field "email" string)
 
type alias User =
    { id : Int
    , profile : Profile
    }
 
userDecoder : Decoder User
userDecoder =
    map2 User
        (field "id" int)
        (field "profile" profileDecoder)

Benefits of Using JSON-to-Elm Tool

✅ Save Time – Automatic type and decoder generation
✅ Reduce Errors – Type-safe conversion
✅ Boost Productivity – Focus on app logic instead of boilerplate
✅ Maintain Clean Code – Readable, reusable, and maintainable Elm types

Best Practices for Developers

Validate JSON before conversion using linters
Use descriptive type names
Split large JSON schemas into modular types
Share generated types and decoders across team projects

Integrating Generated Elm Types into Your Project

Copy the .elm files into your Elm project directory
Import them in your modules:

import Models.Root exposing (Root, rootDecoder)

Use the decoders with Json.Decode for API parsing:

Json.Decode.decodeString rootDecoder jsonString

Step-by-Step How-to Guide

Paste JSON in the left panel
Click Convert
Review generated Elm code on the right panel
Copy or export .elm files
Import into your Elm project and start using immediately

FAQ (Frequently Asked Questions)

Q: Can the tool handle nested arrays? A: Yes, arrays are converted into List T automatically.

Q: Can I customize type names before exporting? A: Yes, type names are editable before generating code.

Q: Does the tool support JSON from URLs? A: Absolutely, paste the URL and the tool fetches and converts JSON.

Q: Is the generated code compatible with Elm 0.19+? A: Yes, fully compatible with Elm 0.19 and above.

Q: Can I convert large JSON files? A: Yes, large and deeply nested JSON schemas are fully supported.

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Get Started Today

Stop manually creating Elm types. Use the JSON-to-Elm generator to save time, reduce errors, and accelerate your Elm development workflow.

Try JSON-to-Elm Generator Now