# Client Class Documentation

The following parameters are configurable for the API Client:

| Parameter | Type | Description |
|  --- | --- | --- |
| `environment` | `Environment` | The API environment. <br> **Default: `Environment.SANDBOX`** |
| `timeout` | `int` | Timeout for API calls in seconds.<br>*Default*: `0` |
| `enableRetries` | `bool` | Whether to enable retries and backoff feature.<br>*Default*: `false` |
| `numberOfRetries` | `int` | The number of retries to make.<br>*Default*: `0` |
| `retryInterval` | `float` | The retry time interval between the endpoint calls.<br>*Default*: `1` |
| `backOffFactor` | `float` | Exponential backoff factor to increase interval between retries.<br>*Default*: `2` |
| `maximumRetryWaitTime` | `int` | The maximum wait time in seconds for overall retrying requests.<br>*Default*: `0` |
| `retryOnTimeout` | `bool` | Whether to retry on request timeout.<br>*Default*: `true` |
| `httpStatusCodesToRetry` | `array` | Http status codes to retry against.<br>*Default*: `408, 413, 429, 500, 502, 503, 504, 521, 522, 524` |
| `httpMethodsToRetry` | `array` | Http methods to retry against.<br>*Default*: `'GET', 'PUT'` |
| `loggingConfiguration` | [`LoggingConfigurationBuilder`](logging-configuration-builder.md) | Represents the logging configurations for API calls |
| `clientCredentialsAuth` | [`ClientCredentialsAuth`](auth/oauth-2-client-credentials-grant.md) | The Credentials Setter for OAuth 2 Client Credentials Grant |

The API client can be initialized as follows:

```php
$client = PaypalServerSdkClientBuilder::init()
    ->clientCredentialsAuthCredentials(
        ClientCredentialsAuthCredentialsBuilder::init(
            'OAuthClientId',
            'OAuthClientSecret'
        )
    )
    ->environment(Environment::SANDBOX)
    ->loggingConfiguration(
        LoggingConfigurationBuilder::init()
            ->level(LogLevel::INFO)
            ->requestConfiguration(RequestLoggingConfigurationBuilder::init()->body(true))
            ->responseConfiguration(ResponseLoggingConfigurationBuilder::init()->headers(true))
    )
    ->build();
```

API calls return an `ApiResponse` object that includes the following fields:

| Field | Description |
|  --- | --- |
| `getStatusCode` | Status code of the HTTP response |
| `getHeaders` | Headers of the HTTP response as a Hash |
| `getResult` | The deserialized body of the HTTP response as a String |

## PayPal Server SDK Client

The gateway for the SDK. This class acts as a factory for the Controllers and also holds the configuration of the SDK.

## Controllers

| Name | Description |
|  --- | --- |
| getOrdersController() | Gets OrdersController |
| getPaymentsController() | Gets PaymentsController |
| getVaultController() | Gets VaultController |
| getOAuthAuthorizationController() | Gets OAuthAuthorizationController |