Plugin vs Preference in Magento 2 – when to use which

One of the most common questions when working with Magento 2 is: should I override a class with a preference, or use a plugin? The answer is almost always the same – use a plugin. But “almost” does a lot of work here. I explain the differences and show when a preference makes sense.

What is a Plugin (Interceptor)?

A plugin is an AOP (Aspect-Oriented Programming) mechanism in Magento 2. It lets you “wrap” an existing public method without overriding it. Three types available:

• before – runs before the method, can modify arguments
• after – runs after the method, can modify the result
• around – takes full control, calls (or skips) the original method

<?php
namespace Vendor\Module\Plugin;

use Magento\Catalog\Model\Product;

class ProductNamePlugin
{
    public function afterGetName(Product $subject, string $result): string
    {
        return $result . ' - On Sale!';
    }
}

Registration in di.xml:

<type name="Magento\Catalog\Model\Product">
    <plugin name="vendor_module_product_name"
            type="Vendor\Module\Plugin\ProductNamePlugin"
            sortOrder="10"/>
</type>

What is a Preference?

A preference is a literal replacement of class A with class B in the DI container.

<preference for="Magento\Catalog\Model\Product"
            type="Vendor\Module\Model\Product"/>

Why is a Plugin almost always better?

Key problem with preferences: there can only be one preference for a given class. If you and a third-party extension both set a preference for the same class – one silently wins. Plugins stack – all of them run, ordered by sortOrder.

When does a Preference make sense?

1. You need to override a private or protected method – plugins only work on public methods.
2. You need to change the constructor – plugins cannot modify __construct().
3. You are implementing an interface differently
4. The class is marked @api

Watch out for the “around” plugin

If you forget to call $proceed(), the original code and all queued plugins will never run. Use around only when you genuinely need to conditionally skip the original method.

Summary – a short rule

Before reaching for a preference, ask: would a plugin not be enough? In 90% of cases it is. A preference leaves behind a trail that is hard to debug during Magento upgrades.