Mastering Magento 2 Observers: A Comprehensive Guide


Magento 2’s robust event-driven architecture allows for dynamic and flexible customizations, making it a preferred choice for e-commerce. At the heart of this system are observers, which enable you to listen for specific events and execute custom code in response. In this comprehensive guide, we’ll explore Magento 2 observers, from understanding their fundamentals to an extensive list of core events you can observe.

What Are Observers in Magento 2?

In Magento 2, observers are PHP classes that listen for and respond to events dispatched during the application’s execution. Events can be system-defined (core events) or custom events created within your module. Observers are crucial for customizing your store, extending its functionality, and reacting to specific moments in your application.

The Anatomy of Observers

Before diving into the observer list, it’s essential to grasp the structure and role of observers:

  1. Observer Class: This is a PHP class containing your custom logic. It listens for specific events and responds when they occur.

  2. Event: An event is a specific moment in the application’s execution. It can be a core event or a custom event you define.

  3. Event Dispatch: Events are dispatched when they occur, notifying registered observers.

  4. Observer Registration: Observers must be registered in your module’s XML files, specifying which events they respond to.

A Comprehensive List of Core Events to Observe

Magento 2 provides a wide range of core events that you can observe. Here’s a comprehensive list of commonly used core events to get you started:

  1. controller_action_predispatch: Dispatched before a controller action is executed. Ideal for modifying the request.

  2. catalog_product_save_after: Triggered after a product is saved in the admin panel. Useful for actions when products are updated.

  3. checkout_onepage_controller_success_action: Dispatched after a successful checkout. Perfect for post-checkout processing.

  4. customer_login: Triggered when a customer logs in. Allows customization of the login process or performing specific actions.

  5. sales_order_place_after: Dispatched after an order is placed. Useful for post-order processing.

  6. catalog_category_save_after: Dispatched after a category is saved in the admin panel. Useful for actions when categories are updated.

  7. checkout_cart_product_add_after: Fired after a product is added to the shopping cart. Useful for cart modification actions.

  8. sales_order_save_after: Dispatched after an order is saved. Helpful for actions related to order processing and updates.

  9. checkout_cart_update_items_after: Fired after the cart items are updated, allowing actions related to cart modifications.

  10. adminhtml_customer_save_after: Dispatched after a customer is saved in the admin panel. Useful for customizing customer management.

Creating Custom Observers

While core events are important, creating custom events and observers is where the real power of Magento 2’s event-driven system shines. Here’s a basic process for creating custom observers:

  1. Define Your Event: In your custom module, define an event corresponding to a specific moment in your application’s execution.

  2. Dispatch Your Event: When your chosen event occurs, dispatch it, triggering any registered observers to execute their custom code.

  3. Create Observer Classes: Develop observer classes that listen for your custom event. These classes contain the logic to execute when the event is dispatched.

  4. Register Observers: Finally, register your observers in your module’s XML files. This informs Magento which events to associate with your observer classes.


Observers in Magento 2 are powerful tools for customizing and extending your online store. Whether you’re working with core events or creating custom ones, understanding and mastering observers empowers you to create a unique and tailored shopping experience for your customers. As you explore and utilize the vast array of events and customize your e-commerce platform, you’re well on your way to becoming a Magento 2 expert.

Copyright © 2013-present All rights reserved.