### Install Tebex PHP SDK via Composer

Source: https://github.com/tebexio/tebex-sdk-php/blob/master/README.md

Use Composer to install the Tebex SDK. Ensure you have Composer installed and configured.

```bash
composer require tebex/tebex-sdk-php
```

--------------------------------

### Headless API - Interact with Tebex Project

Source: https://github.com/tebexio/tebex-sdk-php/blob/master/README.md

Initialize the Headless API with your public token and interact with categories, packages, and create baskets. Handles user authentication if required.

```php
$project = Headless::setProject("your-public-token");

// Interact with the project through $project
$categories = $project->listCategories();
$packages = $project->listPackages();
$project->getCategory(12345);
$project->getPackage(67890);

// Create baskets through the project, providing completion and cancellation urls
$basket = $project->createBasket("https://tebex.io/completed", "https://tebex.io/cancelled");

// If the project requires auth, direct the user to authorize before adding packages
if ($project->requiresUserAuth()) {
    $authUrl = $project->getUserAuthUrl($basket, "https://tebex.io/auth-return");
    echo "- User auth required at: " . $authUrl . ".\n";
}

// Once user is successfully authed we can add packages via $basket
$package = $packages[0];

$basket = $basket->addPackage($package);
$basket = $basket->addGiftedPackage($package, "Tebex");
$basket = $basket->addGiftCardPackage($package, "tebex-integrations@overwolf.com");

// You can also add variable data as needed per each package
$basket->addPackage($package, [
    "server_id" => "127244"
]);

// Each function returns the remote basket after completion, but you can always request the current basket from the API
$basket = $basket->refreshBasket();

// Query the $basket object for any info
echo "Price: $" . $basket->getBasePrice() . "\n";

// Go to checkout
$checkoutLink = $basket->getLinks()->getCheckout();
echo "Checkout at: " . $checkoutLink;
```

--------------------------------

### Checkout API - Set API Keys

Source: https://github.com/tebexio/tebex-sdk-php/blob/master/README.md

Authorize the Checkout API using your project ID and private key. This step is required before making any Checkout API calls.

```php
// Authorize your store using your API keys
Checkout::setApiKeys("projectId", "privateKey");
```

--------------------------------

### Create a Checkout Request

Source: https://github.com/tebexio/tebex-sdk-php/blob/master/README.md

Use Checkout::checkoutRequest to send basket information and products in a single request. The list of packages should be an array of CheckoutItem, which can be provided by the PackageBuilder with buildCheckoutItem().

```php
$builder = Checkout\BasketBuilder::new()
    ->email("support@tebex.io")->firstname("Tebex")->lastname("Support")
    ->ip($_SERVER["REMOTE_ADDR"])
    ->returnUrl("https://tebex.io/")->completeUrl("https://tebex.io/");

$package1 = Checkout\PackageBuilder::new()->name("100 Gold")->qty(1)->price(1.27)->oneTime();
$basket = Checkout::checkoutRequest($builder, [$package1->buildCheckoutItem()]);

echo "Checkout at: " . $basket->getLinks()->getCheckout();
```

--------------------------------

### Include Composer Autoloader

Source: https://github.com/tebexio/tebex-sdk-php/blob/master/README.md

Include Composer's autoloader to make the Tebex library available in your PHP project.

```php
require_once 'vendor/autoload.php';
```

--------------------------------

### Checkout API - Create Packages with PackageBuilder

Source: https://github.com/tebexio/tebex-sdk-php/blob/master/README.md

Define packages for the Checkout API using PackageBuilder. Supports one-time purchases and recurring subscriptions with specified quantities and prices.

```php
$package1 = Checkout\PackageBuilder::new()->name("100 Gold")->qty(1)->price(1.27)
    ->oneTime();
    
$package2 = Checkout\PackageBuilder::new()->name("1 Month Sub")->qty(1)->price(2.44)
    ->subscription()->monthly()->expiryLength(1);
```

--------------------------------

### Checkout API - Create Basket with BasketBuilder

Source: https://github.com/tebexio/tebex-sdk-php/blob/master/README.md

Use the BasketBuilder to construct a basket for the Checkout API. Set customer details, return URLs, and completion URLs.

```php
// Use the BasketBuilder to create your basket for Checkout
$builder = Checkout\BasketBuilder::new()
    ->email("tebex-integrations@overwolf.com")
    ->firstname("Tebex")
    ->lastname("Integrations")
    ->ip("127.0.0.1") // provide client IP if running on your backend server
    ->returnUrl("https://tebex.io/")
    ->completeUrl("https://tebex.io/");
```

--------------------------------

### Webhook - Set Secret Key and Parse Incoming Webhook

Source: https://github.com/tebexio/tebex-sdk-php/blob/master/README.md

Configure the webhook secret key for validation and parse incoming webhook data from php://input. This is crucial for verifying the authenticity of webhook events.

```php
// You must set your secret key first so that webhooks can be validated.
Webhooks::setSecretKey("2248c2227ac29e5cbdbab44ed6a0f961");

// Is read from php://input unless an argument is provided
$webhook = Webhook::parse();

// You can check for specific webhook types
if ($webhook->isType("\Tebex\Webhook\VALIDATION_WEBHOOK")) {
    echo json_encode(["id" => $webhook->getId()]); // Respond to validation endpoint
}

// You can quickly check the type of webhook with helper functions as well
else if ($webhook->isTypeOfPayment() || $webhook->isTypeOfDispute())
{
    // The "subject" contains data about the webhook action
    $pmtSubject = $webhook->getSubject(); // type is \TebexCheckout\Model\PaymentSubject
    // etc....
}
else if ($webhook->isTypeOfRecurringPayment()) {
    $recurringPmtSubject = $webhook->getSubject(); // \TebexCheckout\Model\RecurringPaymentSubject
    // etc...
}
```

=== COMPLETE CONTENT === This response contains all available snippets from this library. No additional content exists. Do not make further requests.