JSON to PHP Converter

Generate PHP Classes from JSON

This tool converts JSON data into PHP class definitions. It supports modern PHP 8+ features like constructor property promotion and typed properties.

Output Options

PHP 8+ Constructor Promotion

Concise syntax with properties declared directly in the constructor:

class User
{
    public function __construct(
        public int $id,
        public string $userName,
        public bool $isActive
    ) {}
}

Traditional PHP Class

Classic style with separate properties and constructor:

class User
{
    private int $id;
    private string $userName;
    private bool $isActive;

    public function __construct(int $id, string $userName, bool $isActive)
    {
        $this->id = $id;
        $this->userName = $userName;
        $this->isActive = $isActive;
    }
}

Type Mapping

Using Generated Classes

// Create from array
$data = json_decode($jsonString, true);
$user = new User(
    $data['id'],
    $data['userName'],
    $data['isActive']
);

// Access properties
echo $user->userName;

With JSON Serialization

// Add JsonSerializable interface
class User implements JsonSerializable
{
    // ... properties and constructor ...
    
    public function jsonSerialize(): array
    {
        return [
            'id' => $this->id,
            'userName' => $this->userName,
            'isActive' => $this->isActive,
        ];
    }
}

// Serialize back to JSON
echo json_encode($user);

Related Tools

• JSON Validator — Validate JSON before converting
• JSON to Java — Generate Java POJOs
• JSON to Python — Generate Python dataclasses
• JSON to C# — Generate C# classes

Frequently Asked Questions

What PHP version is required?

Constructor promotion requires PHP 8.0+. Typed properties require PHP 7.4+. Disable these options for older PHP versions.

How do I handle arrays of objects?

PHP doesn't support generic array types in type hints. Arrays are typed as array. Add PHPDoc annotations manually for IDE support:/** @var User[] */

Common Mistakes & Pro Tips

• Typed properties throw if null lands in a non-nullable type — Since PHP 7.4 you can declare `public int $age;`, but assigning `null` to it (e.g. from a nullable JSON field) throws a `TypeError`. Mark fields that may be null as nullable with a leading `?` (`public ?int $age;`), which also makes them default to an uninitialized state you should guard against.
• json_decode gives float for decimals, int for whole numbers — `json_decode` maps JSON integers to PHP `int` and any number with a decimal/exponent to `float`. Very large integers beyond PHP_INT_MAX become `float` (losing precision) unless you pass the `JSON_BIGINT_AS_STRING` flag to keep them as strings. Type money fields as `string` and use BCMath/`brick/math` rather than `float`.
• json_decode(true) gives arrays, not your classes — `json_decode($json, true)` returns nested associative arrays, and `json_decode($json)` returns generic `stdClass` objects — neither produces instances of your generated classes automatically. To hydrate typed objects you must map fields manually in a constructor/factory, or use a library like Symfony Serializer, JMS Serializer, or `cuyz/valinor`.
• Map JSON keys when names differ; mind reserved words — PHP has no built-in JSON property-name attribute in core, so if a JSON key differs from your property name (e.g. snake_case to camelCase) you map it in your hydration code or via a serializer's attributes (Symfony's `#[SerializedName]`). JSON keys that are PHP reserved words or contain hyphens can't be property names — rename and map them explicitly.
• Empty arrays and dates stay loose — PHP arrays are untyped, so a JSON array becomes `array` with no element type guarantee — document the element type in a `@var Item[]` PHPDoc for IDE/static-analysis support. Date strings remain `string`; convert to `DateTimeImmutable` yourself in the constructor, since `json_decode` never produces date objects.