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PHP Enums

Last updated: April 6, 2026
Minimum PHP Version: PHP 8.1+

Overview

Enums (enumerations) allow you to define a type with a fixed set of possible values. Introduced in PHP 8.1, enums provide type-safe alternatives to constants and make code more expressive and maintainable.

PHP Version Support

Feature PHP 8.0 PHP 8.1+ PHP 8.2+
Enums (Pure) ❌ ✅ ✅
Backed Enums ❌ ✅ ✅
Enum Methods ❌ ✅ ✅
Constants in Enums ❌ ✅ ✅
Enum Traits ❌ ✅ ✅

When to Use

  • Defining fixed sets of values (statuses, roles, directions)
  • Type-safe alternatives to class constants
  • State machines with clear transitions
  • Configuration options with limited valid values
  • Domain-driven design with value objects

Basic Example

<?php
enum Status {
    case Draft;
    case Published;
    case Archived;
}

function publish(Status $status): void {
    if ($status === Status::Draft) {
        echo "Publishing draft...";
    }
}

publish(Status::Draft);  // Output: Publishing draft...
?>

Advanced Example (Backed Enums)

<?php
enum HttpStatus: int {
    case OK = 200;
    case Created = 201;
    case BadRequest = 400;
    case NotFound = 404;
    case ServerError = 500;
}

function handleResponse(HttpStatus $status) {
    echo "Status: " . $status->value;
}

handleResponse(HttpStatus::OK);  // Output: Status: 200
?>

PHP Version Support

Introduced: PHP 8.1
Minimum Required: PHP 8.1+
Backed Enums: PHP 8.1+

See Also

PHP Enums allow you to define a type that has a fixed set of values. Enums were introduced in PHP 8.1.

Basic Enums

<?php
enum Status
{
    case Draft;
    case Published;
    case Archived;
}

function publish(Status $status): void
{
    if ($status === Status::Draft) {
        echo "Cannot publish a draft!";
    }
}

publish(Status::Draft);
?>

Backed Enums

Backed enums have a scalar value (string or int) associated with each case.

<?php
enum Priority: int
{
    case Low = 1;
    case Medium = 2;
    case High = 3;
    case Critical = 4;
}

enum Color: string
{
    case Red = '#FF0000';
    case Green = '#00FF00';
    case Blue = '#0000FF';
}

$priority = Priority::High;
echo $priority->value; // 3
echo $priority->name;  // High
?>

Enum Methods

Enums can have methods.

<?php
enum Status
{
    case Draft;
    case Published;
    case Archived;

    public function label(): string
    {
        return match($this) {
            self::Draft => 'Draft',
            self::Published => 'Published',
            self::Archived => 'Archived',
        };
    }

    public function isActive(): bool
    {
        return $this !== self::Archived;
    }
}

echo Status::Published->label();   // "Published"
echo Status::Draft->isActive();    // true
echo Status::Archived->isActive(); // false
?>

Enum with Interfaces

<?php
interface Labeled
{
    public function label(): string;
}

enum Status implements Labeled
{
    case Draft;
    case Published;
    case Archived;

    public function label(): string
    {
        return match($this) {
            self::Draft => 'Draft',
            self::Published => 'Published',
            self::Archived => 'Archived',
        };
    }
}
?>

Enum as Type

<?php
enum OrderStatus: string
{
    case Pending = 'pending';
    case Processing = 'processing';
    case Completed = 'completed';
    case Cancelled = 'cancelled';

    public static function active(): array
    {
        return [
            self::Pending,
            self::Processing,
        ];
    }
}

function processOrder(OrderStatus $status): void
{
    // Type safety - only valid statuses allowed
}

processOrder(OrderStatus::Pending);    // OK
processOrder(OrderStatus::Completed);  // OK
processOrder('invalid');              // TypeError
?>

Iterating Over Cases

<?php
enum Status
{
    case Draft;
    case Published;
    case Archived;
}

// Loop through all cases
foreach (Status::cases() as $case) {
    echo $case->name . PHP_EOL;
}
?>

Enums vs Class Constants

Feature Class Constants Enums
Type safety No Yes
IDE support Limited Excellent
Exhaustiveness No Yes
Methods No Yes
Cases as values No Yes