JSON to Haskell Converter: Generate Type-Safe Haskell Data Types

Working with JSON in Haskell can be repetitive. Our JSON-to-Haskell tool automatically generates Haskell data types from JSON, making development faster, safer, and more maintainable.

Why Developers Need a JSON-to-Haskell Tool

Manually writing Haskell types from JSON:

• Is time-consuming
• Can introduce type mismatch errors
• Requires boilerplate for nested objects and arrays
• Slows down Haskell development workflow

Automation ensures speed, accuracy, and type safety.

Key Features of JSON-to-Haskell Generator

• Automatic Haskell data type generation
• Supports nested objects and arrays
• Correctly infers types: Int, Double, String, Bool, Maybe T, [T]
• Handles JSON from files or URLs
• Copy or export .hs files ready for your project

How the JSON-to-Haskell Tool 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

Generated Haskell types appear on the right panel, ready to copy or export.

Example: Simple JSON Conversion

Input JSON:

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

Generated Haskell Types:

data Root = Root
  { id   :: Int
  , name :: String
  , tags :: [String]
  } deriving (Show, Eq)

Example: Nested JSON Conversion

Input JSON:

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

Generated Haskell Types:

data Profile = Profile
  { age   :: Int
  , email :: String
  } deriving (Show, Eq)
 
data User = User
  { id      :: Int
  , profile :: Profile
  } deriving (Show, Eq)

Benefits of Using JSON-to-Haskell Tool

• ✅ Save Time – Automatic type generation
• ✅ Reduce Errors – Type-safe conversion
• ✅ Boost Productivity – Focus on logic instead of boilerplate
• ✅ Maintain Clean Code – Readable and reusable Haskell 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 across team projects for consistency

Integrating Generated Haskell Types Into Your Project

1. Copy the .hs files into your Haskell project
2. Use Aeson for JSON parsing:

{-# LANGUAGE DeriveGeneric #-}
 
import Data.Aeson
import GHC.Generics
 
instance FromJSON Root
instance ToJSON Root
 
let decoded = decode jsonData :: Maybe Root

3. Use the types throughout your project for type-safe data handling

Step-by-Step How-to Guide

1. Paste JSON in the left panel
2. Click Convert
3. Review generated Haskell types on the right panel
4. Copy or export .hs files
5. Integrate into your Haskell project and start using immediately

FAQ (Frequently Asked Questions)

Q: Can the tool handle nested arrays? A: Yes, arrays are converted into [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 GHC 9+? A: Yes, fully compatible with modern GHC versions.

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

Related Tools for Developers

• JSON to TypeScript Converter – Convert JSON to TypeScript interfaces
• JSON to Dart Converter – Convert JSON to Dart classes
• JSON Formatter & Validator – Format and validate JSON

Get Started Today

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

Try JSON-to-Haskell Generator Now