Magento 2 Repository and Factory are two different design patterns used in Magento 2 to manage the creation and retrieval of data objects.

A Repository is a pattern that defines a set of methods for working with data in a way that is abstracted from the underlying data source. In Magento 2, Repositories are typically used to manage the retrieval and storage of data in the database. They provide a consistent way to interact with data, allowing for the implementation of different data sources without affecting the rest of the code. Repositories can also be used to perform data validation and implement business logic.

A Factory is a pattern that provides a way to create objects. In Magento 2, Factories are typically used to create instances of a model or data object. They provide a centralized way to create objects and can be used to implement object creation logic. Factories can also be used to create objects that depend on other objects or data.

The main difference between Magento 2 Repository and Factory is their purpose. Repositories are used to manage the retrieval and storage of data, while Factories are used to create objects. Repositories can also be used to perform data validation and implement business logic, while Factories are typically used to implement object creation logic.

<?php

namespace Vendor\Module\Api;

interface ProductRepositoryInterface
{
    /**
     * Retrieve a product by id.
     *
     * @param int $productId
     * @return \Vendor\Module\Api\Data\ProductInterface
     * @throws \Magento\Framework\Exception\NoSuchEntityException
     */
    public function getById($productId);
}
<?php

namespace Vendor\Module\Model\Product;

class ProductFactory
{
    /**
     * Create new instance of a product.
     *
     * @return \Vendor\Module\Api\Data\ProductInterface
     */
    public function create()
    {
        return $this->_objectManager->create(\Vendor\Module\Api\Data\ProductInterface::class);
    }
}

In this example, the ProductRepositoryInterface is a Repository and is used to retrieve a product by id. The ProductFactory is a Factory and is used to create a new instance of a product.

In conclusion, Repositories are used to retrieve objects from a data source and apply business logic, while Factories are used to create new instances of objects. Both patterns are important in Magento 2, and the choice between a Repository and a Factory will depend on the specific requirements of the task at hand.