Magento 2 or Adobe Commerce Architect or Developer Interview Questions & Answers

1. What is Magento 2 and how does it differ from Magento 1?

• Answer: Magento 2 is the latest version of the Magento eCommerce platform, offering improved performance, scalability, and new features compared to Magento 1. Key differences include:
  • Architecture: Magento 2 has a more modular codebase with a modern tech stack.
  • Performance: Improved indexing, caching, and optimized checkout process.
  • User Experience: Responsive design and better admin interface.
  • Database: Supports multiple databases for different functions (e.g., checkout, orders, and product data).
  • Extensions: Simplified integration with third-party extensions and APIs.

2. Can you explain the Magento 2 architecture?

• Answer: Magento 2 architecture is based on a modular system, separating code into individual modules. The architecture includes:
  • Presentation Layer: Contains blocks, layouts, and templates.
  • Service Layer: Provides a set of interfaces and service contracts.
  • Domain Layer: Business logic, typically found in models.
  • Data Layer: Database access, repository pattern, and entities.
  • Integration Layer: APIs, web services, and external system integrations.
  • Dependency Injection (DI): Magento 2 uses DI to manage class dependencies, improving testability and flexibility.
  • Event-Observer and Plugins: Allows customization and extension of core functionalities.

3. What is Dependency Injection in Magento 2? How does it work?

• Answer: Dependency Injection (DI) is a design pattern used in Magento 2 to manage object dependencies. It allows objects to be passed to other objects through constructors or setters, rather than creating instances directly. This increases flexibility and makes the system more testable.
  • How it works: Magento 2 uses an XML-based configuration to declare dependencies. The DI framework automatically injects the required dependencies when an object is instantiated.

4. How do you manage caching in Magento 2?

• Answer: Magento 2 uses several types of caching to improve performance, including:
  • Configuration Cache: Caches system configuration.
  • Page Cache: Caches full page content (supports Varnish).
  • Block Cache: Caches individual blocks.
  • Collection Cache: Caches database queries.
  • Session Cache: Stores session data.
  • Caches can be managed through the Magento Admin Panel under “System > Cache Management” or via the CLI using bin/magento cache:enable/disable/clean/flush commands.

5. Explain the concept of Service Contracts in Magento 2.

• Answer: Service Contracts are a set of PHP interfaces used to define the APIs (Application Programming Interfaces) of the business logic in Magento 2. They provide a stable API, ensuring backward compatibility and are designed to be used by modules, web services, or third-party developers.
  • Key Components:
    • Data Interfaces: Define the structure of the data (e.g., CustomerInterface, OrderInterface).
    • Service Interfaces: Define operations related to the business logic (e.g., CustomerRepositoryInterface, ProductRepositoryInterface).

6. What is the purpose of Composer in Magento 2?

• Answer: Composer is a dependency manager used in Magento 2 to manage PHP libraries, modules, and dependencies. It helps in:
  • Dependency Management: Automatically installs and updates packages and libraries that Magento or its modules depend on.
  • Autoloading: Composer provides autoloading for classes, reducing the need to manually include files.
  • Version Control: Manages version control of dependencies, ensuring compatibility between modules and core Magento functionality.

7. How do you approach customization in Magento 2?

• Answer: Customization in Magento 2 should follow best practices to ensure maintainability and upgradability:
  • Using Plugins: Allows you to modify the behavior of public methods in a class without overriding the entire class.
  • Observers: Listen to events and execute code when the event is triggered.
  • Overrides: Use carefully to avoid conflicts, usually by creating custom modules rather than directly modifying core files.
  • Layouts and Templates: Customizing the presentation layer using XML layout files and PHTML templates.
  • Service Contracts: Prefer using service contracts for business logic changes to maintain a stable API.

8. What are Magento 2 modules and how do you create one?

• Answer: Magento 2 modules are the building blocks of a Magento application. They contain the code needed to add features or functionality. To create a module:
  • 1. Create the module directory structure:
    • app/code/VendorName/ModuleName
  • 2. Create the module’s registration.php file to register the module with Magento.
  • 3. Create the module.xml file in etc folder to define module details.
  • 4. Configure composer.json to manage dependencies.
  • 5. Define necessary configurations in etc (e.g., routes, events, di.xml).
  • 6. Run bin/magento setup:upgrade to install the module.

9. How do you manage security in a Magento 2 application?

• Answer: Security in Magento 2 can be managed through:
  • Applying Patches: Regularly apply security patches provided by Magento.
  • Two-Factor Authentication (2FA): Enable 2FA for the admin panel.
  • Secure Admin URLs: Change the default admin URL and limit access by IP.
  • Use HTTPS: Enforce HTTPS for all frontend and backend operations.
  • Role-Based Access Control: Create specific user roles and permissions to limit access to sensitive areas.
  • Data Sanitization: Always sanitize user input and use Magento’s built-in methods to avoid SQL injection, XSS, and other attacks.

10. Explain the role of Magento 2 CLI.

• Answer: Magento 2 Command Line Interface (CLI) provides a set of commands to perform various tasks, including:
  • Setup and Configuration: bin/magento setup:install, bin/magento config:set.
  • Cache Management: bin/magento cache:clean, bin/magento cache:flush.
  • Module Management: bin/magento module:enable, bin/magento module:disable.
  • Index Management: bin/magento indexer:reindex.
  • Deployment: bin/magento setup:upgrade, bin/magento deploy:mode:set.

11. What is Varnish and how is it used in Magento 2?

• Answer: Varnish is a web application accelerator (cache) used to improve website performance by caching content and serving it directly from memory. In Magento 2:
  • Full Page Cache (FPC): Varnish can be used as the FPC, reducing the load on the web server and speeding up page delivery.
  • Configuration: Varnish can be configured in Magento 2 under Stores > Configuration > Advanced > System > Full Page Cache.
  • Integration: Magento 2 provides VCL (Varnish Configuration Language) files to integrate Varnish, which can be customized according to the environment.

12. How do you optimize performance in Magento 2?

• Answer: Optimizing performance in Magento 2 involves:
  • Caching: Use Varnish for FPC, enable Redis for session and cache storage.
  • Indexing: Set indexers to “Update on Schedule” for better performance.
  • Optimization Tools: Use tools like Minify HTML/CSS/JS and merge CSS/JS files.
  • CDN: Use a Content Delivery Network to deliver content faster to users.
  • Database Optimization: Regularly clean logs, optimize database tables, and use proper indexes.
  • Image Optimization: Compress images and use responsive images to reduce load time.
  • Server Configuration: Ensure proper server resources (CPU, memory), PHP version (7.4+), and enable OPcache.

13. What is the Magento 2 Layout XML and how does it work?

• Answer: Layout XML in Magento 2 is used to define the structure and content of a page. It controls which blocks are displayed, in what order, and where.
  • Key Elements:
    • <block>: Defines a block of content.
    • <container>: Defines a container that can hold blocks.
    • <referenceBlock> and <referenceContainer>: Modify existing blocks/containers.
    • <remove>: Removes blocks or containers.
  • Usage: Layout XML is defined in module or theme specific XML files, such as default.xml, catalog_product_view.xml, etc.

14. How do you handle multi-store functionality in Magento 2?

• Answer: Magento 2’s multi-store functionality allows you to manage multiple websites, stores, and store views from a single Magento installation.