Interview Questions with Responses for Magento Developers

Mixed Interview Questions

Question 1. Could you please name the methods of altering the way that Magento works, focusing on potential ways to expand Magento core features? Please, comment on the differences and peculiarities of these methods.

Answer: Basically, there are three methods to modify the way Magento works by overriding core functionalities. These three ways are performing money patches, doing rewrites, and using observers. To start with, the least favored method is the use of monkey patches. The idea of monkey patches is based on overriding the modules that are positioned in the core. To do this, community code pools are usually used. In other words, community codes are simply copied into the local code. Therefore, the method of Rewrites is easier and quicker than the monkey patches.

Second, the Rewrites method is used to rewrite a function by determining a class that is described in your config file. The Rewrites method work by rewriting an existing class, which is less effortful than the use of monkey patches because only one function is rewritten. However, the method Observers is the most useful because it implies the action when certain functions are performed. Using the Observers method, it is easier to alter the event that is launched already.

Question 2. Could you please name the best way to count the items in a collection

Answer: When we want to count the items in a collection, we apply the method getSize() because, with this method, all items of the collection are not stacked every time when they are counted but loaded only once. GetSize() is better because it loads items only once while the Count() method loads items every time when counting. As a result, getSize() allows minimizing the memory usage by loading and counting the items in the collection only once.

Question 3. Could you please comment on the EAV naming its pros and cons?

Answer. To begin with, EAV is the abbreviation for entity-attribute-value. It is the approach that describes the way that customers, products, and address data are stored in a Magento database. The use of EAV implies that the information is retrieved with a query that consists of three tables of customers, products, and addresses. Often, this enables a user to change the attributes easily with no need to modify the database schema, which means having a flexible database. However, the process is resource-consuming and practically, it minimizes the advantages of the use of the relational database. Moreover, with the EAV, even the most basic queries are going to be challenging to write, which minimizes the benefits of the EAV use.

Question 4. Could you please define deploy modes in Magento 2?

Answer. In Magento 2, there are three major modes, namely developer, default, and production. The Default mode is installed by default, and others need to be switched on to be used. For example, the Developer mode is used when programming errors need to be caught in the front end. Therefore, in the Developer mode, static view file caching is disabled, and enhanced debugging is enabled instead. As a result, all caught exceptions and errors are displayed in the front end and the developers might see the errors in real-time. Just to compare, in the Default mode, caching works as supposed, and exceptions are not displayed to the user but are written to the log file instead. In the Production mode, necessary files are generated and placed in the pub/static folder, which is a must for all Magento 2 websites working in production because this mode prevents automatic file compilation. One more mode that is rarely used is the Maintenance mode that is used only when there is a need to prevent access to the website during maintenance or upgrading.

Basic Interview Questions

Question 5. Could you please name the scripting language and the database that is used for Magento 2?

Answer: Magento 2 is based on PHP 5.4., 5.5., and above for scripting and on MySQL 5.6 for the database architecture.

Question 6. Could you please comment on the process of module creation in Magento?

Answer: A module creation in Magento is simple and consists of three basic steps. First, we name the module and define it in the app/code folder. Second, we create a new file and give it a name registration.php. Third, we enable the module inside the folder.

Question 7. Could you please comment on Magento dependency injections?

Answer: Dependency injection is a design pattern in Magento 2 that is aimed to implement control inversion. The principal gains of using Magento dependency injections comprise code reusability,easier-to-test code, and improved hassle-free app maintenance.

Advanced Interview Questions

Question 8. Could you please give your thoughts on the improvement of the Magento apps efficiency?

Answer: Practically, the improvement of the efficiency of Magento apps is rich in features that improve performance. The most often used approaches to improving the effectiveness are the next ones:

Disabling unused modules
Enabling cache
Optimizing servers and images
Rising the stylesheets in the list
Avoiding the use of CSS expressions
Avoiding over-reliance on Magento Log
Moving the scripts down to the bottom
Deleting the unused scripts

Question 9. What if you need to design a module with the next specs: the module sends a newsletter automatically, the newsletter is sent to all subscribers within specified intervals of time, you need to understand if subscribers got the letter?

Answer: The right choice is when a candidate speaks about making sure the system crontab contains bin/magento cron: run. After that, there is a need to run \MyCompany\MyModule\Cron\NewsLetterSender::execute and register it in etc/crontab/.xml.

Question 10. Could you please name the items of the ACL that will have restricted permissions if a developer wants to restrict the access to a custom ACL resource he is going to create?

Answer: The next ACL items are going to have restricted permissions: system configuration sections, storefront login, and adminhtml controllers.

Bonus Interview Questions

Question 11. Could you please share your thoughts on Magento environment optimization?

Answer: To optimize Magento environment, the next approaches will work:

First, Magento database works best when run on dedicated servers.
Second, cloud computing is the best choice when it comes to running Magento applications.
JavaScript and CSS files should be merged because this decreases the load time considerably.
MySQL should be configured appropriately
The latest Magento version is a must.

Question 12. Could you please comment on the ways to optimize Magento configuration?

Answer: There is a variety of ways to optimize Magento configuration, including but not limited to:

Magento-optimized hosting
Mysql and web server should be run on different machines
Time to First Byte (TTFB) should be reduced as much as possible
Database should be optimized
Session storage should be optimized
Performance metrics should be used to assess performance and improve it
Magento flat catalog should be enabled.
Unused Magento modules should be identified and disabled

Summary

Asking questions during the interview is an awesome approach, but it requires the previous effort of filtering out the best candidates. It is easier to find a highly qualified Magento developer when a developer has already worked with Magento and has a developed portfolio including online stores for international brands.

Originally published at https://soft-loft.com on March 10, 2021.

Top 12 Magento Interview Questions and Answers