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# Accessing the PHP SDK object model

> Learn how to access the PHP SDK object model.

> **Note**
>
> Learn about [Quickstart](/docs/esign-rest-api/quickstart) and how you can use it to quickly set up and run eSignature REST API code examples.

## Instantiating the models

When making a specific eSignature REST API call using the PHP SDK, you usually have to include a specific class used for the data sent or returned as part of that API request. The PHP classes used to pass data to and from API endpoints are called *models*. We will use the `Brand` object as an example. The [Brand](https://github.com/docusign/docusign-php-client/blob/master/src/Model/Brand.php) class can be found in our open-source GitHub repository.

The `brand_name` property is an example of a string that is part of the `Brand` class that has both a public getter and a public setter. To set the `brand_name` property of a `Brand` object, use this code:

`brand->setBrandName($brand_name);`

To get the value of the `brand_name` property, you can simply use the string that it returns, like this:

`Console::writeLine ("The brand name is ", brand->getBrandName);`

Most PHP SDK models also provide a constructor that enables developers to initialize many of the object’s properties at the same time that it is created. Instead of using the getter and setter methods, you could set property values in the constructor code when you create the object.

For example, you could instantiate a new `Brand` object and set some of its properties at the same time, like this:

```text
    $brand = new Brand([
        'brand_name' => $a_brand_name,
        'default_brand_language' => $a_brand_language
    ]);
```

## Making API calls

To construct an API call, you need to include both the model and the `account_id` of the account making the API call, each time you make a request. That information is not part of the `ApiClient` object, but is required by the SDK to be able to generate the URL for the specific endpoint.

To create a new brand, for instance, you would instantiate a `Brand` object and populate it with initial values as shown above, then add the `account_id` to call the API, as shown below:

`$results = $accounts_api->createBrand($args['account_id'], $brand);`

## Naming conventions

The PHP SDK uses the naming conventions in [PSR-1](https://www.php-fig.org/psr/psr-1/) and additionally uses snake_case for parameters.

* The categories in the API Reference are all called `Apis` in the PHP SDK. As an example, the [AccountsApi](https://github.com/docusign/docusign-esign-php-client/blob/master/src/Api/AccountsApi.php#L1121)  class would be the class you use to make API calls for endpoints in the [Accounts Category](/docs/esign-rest-api/reference/accounts) in the API Reference.
* The resources within each category in the API Reference do not have direct counterparts in the PHP SDK. Instead, each API method in each resource corresponds to a PHP public method within the class corresponding to the top-level category. The method name is always camelCased and is a combination of the verb and the object that is being worked upon. For example, for the [AccountBrands: update](/docs/esign-rest-api/reference/accounts/accountbrands/update) API method, the PHP method within the `AccountsApi` class is [updateBrand](https://github.com/docusign/docusign-esign-php-client/blob/master/src/Api/AccountsApi.php#L6625).
* The parameters for each API method are based on the API Reference. Every API call has to specify the `account_id` as its first parameter, required to determine which account is making the API request. The remaining parameters are defined per API call in the documentation and may include optional parameters. Parameter names are always written in snake_case.
* The request and response objects (if they exist; some methods have one or the other) are all defined as public classes. These classes are a deserialized version of the JSON that is sent by the REST API. For example, the [updateBrand](https://github.com/docusign/docusign-esign-php-client/blob/master/src/Api/AccountsApi.php#L6625) method returns an object called [Brand](https://github.com/docusign/docusign-esign-php-client/blob/master/src/Model/Brand.php#L46), which represents the response of the API call. For any array returned by the JSON, the model would include an array with elements corresponding to that information. All models also implement two interfaces: `ModelInterface` and `ArrayAccess` to support comparison as well as cleanup of unused objects.