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What are the most popular PHP developer interview questions?
2022-02-16 /

Top 10 PHP Developer Interview Questions

PHP development skills are in demand. But how do you hire the best talent? This article will detail what to look for from applicants and which PHP interview questions to ask. Let’s look at some of the most asked interview questions for PHP developers.

As a programming language, PHP has become an essential skill set with businesses turning to web-based solutions. Consequently, the demand for developers who are well-versed in PHP continues to rise.

Depending on the company, the requirements for developer candidates vary. Some companies may need more experienced developers, while others accept junior levels. But one thing is sure—every candidate must undergo a rigorous testing and interview process.

The job interview process can be confusing especially for companies with less experience in software development. Each candidate will present themselves as the ones with the best PHP skills.

So, aside from giving technical exams, how can your hiring team measure the skills of each candidate? The best way to test their knowledge is to ask PHP interview questions. But before going into the interview process, let us first have a background on PHP.

What is PHP?

Briefly, PHP (or PHP: Hypertext Preprocessor) is one of the popular open-source scripting languages. It is the go-to programming language that backend developers use. In fact, of all the websites existing today, 78.1% use PHP

The number alone shows the flexibility of PHP as a server-side language. It is used to build different types of projects from blogs, software-as-a-service (SaaS), and other applications.

Therefore, PHP developers are software developers who specialize in server-side development using PHP. Due to the many uses of PHP, developers are sometimes referred to as software developers or web developers. They can work either developing user interfaces or the backend part of websites.

That is just a brief description of what a PHP developer is. Read more about PHP developers in this entry: What is a PHP Developer? Now, let us discuss their duties and responsibilities.

PHP Developer: Duties and Responsibilities

A PHP developer’s duties include:

  • Developing, testing, and launching website applications
  • Studying, researching, and gathering project requirements
  • Helping in identifying compatibility issues(CSS, HTML, and scripting)
  • Doing tests and analyses to identify coding problems with websites
  • Help in integrating data storage solutions
  • Assist in the implementation of web usability, performance, and database design
  • Finalizing the project’s backend features
  • Make sure that application features are working without issues
  • Enhancing and updating application features for better performance

The above-mentioned items are just the everyday duties assigned to PHP developers. Some companies may add more specific tasks depending on their needs.

PHP Developer: Skills and Requirements

To work on the aforementioned tasks properly, they should have the following technical skills:

  • College degree in IT, computer science, or any related fields
  • Expertise in the PHP programming language
  • Experience with PHP frameworks (CodeIgniter, Yii, Laravel, etc.)
  • Must know object-oriented PHP programming
  • Have experience working with unit testing frameworks (PHPUnit)
  • In-depth knowledge about databases (jQuery, Ajax, MySQL, etc.)
  • Skills in developing scalable applications
  • Knowledge of how to use development tools like Mercurial, CVS, Git, SVN, etc.

Additionally, they should have the following soft skills:

  • Problem-solving
  • Critical thinking
  • Adaptability
  • Team player
  • Good communication
  • Detailed-oriented
  • Accountability

With the listed information, you can have a better understanding of what to expect from PHP developers. Let’s proceed with the interview process.

Top PHP Interview Questions

Interview questions aim to check if applicants possess the skills to fulfill their responsibilities as PHP developers. Hence, you need to prepare questions that will allow the applicants to highlight their technical and behavioral skills. Here are some of the most asked PHP interview questions and sample answers:

1. Explain static and dynamic websites. What are their differences?

Everything in static websites is predefined. That is why you cannot change the content after running the script. On the other hand, while running dynamic websites’ scripts, the script is changeable. As a result, every time a user visits the site, the contents get regenerated.

2. Does PHP support multiple inheritances?

No. PHP only allows one class extension from a single class when using the keyword “extended.”

3. What are ECHO and PRINT in PHP? What are their differences?

Both are PHP functions. We use these functions to output or display data on the screen. However, they have differences. For instance, ECHO can take multiple parameters and is faster than PRINT. However, it has no return value.

On the other hand, the PRINT return value is one. This means that the function is okay to use in expressions. However, PRINT can only support one argument.

4. Does PHP interact with JavaScript? If yes, explain.

Since PHP is a server-side programming language and JavaScript is client-side, they cannot interact directly. However, we can still exchange variables between the two languages. This is because PHP can generate JavaScript code that a browser will execute. In addition, it is also possible to pass variables back to PHP via the URL.

5. Why use PHP?

PHP provides many benefits to any business enterprise. For example, it is an open-source language. This means anyone can use it without much cost.

The programming language also supports different databases. Most developers use PHP with MySQL as it is also free to use. Aside from these, PHP frameworks are used for web development.

6. What are the disadvantages of PHP?

Although PHP is a flexible programming language, it still has limitations. Firstly, security can be a problem because it is an open-source language. Also, it does not allow modification of the online applications’ core behavior. Another disadvantage of using PHP is that it has fewer debugging tools compared to other programming languages.

7. Have you used “@” in PHP? What is its function?

Yes. We use “@” to suppress error messages in PHP. This means that PHP will take care of the runtime errors of the lines using the symbol “@” at the beginning. 

8. Are there rules in naming variables in PHP?

Yes. There are defined rules when naming variables in PHP. First, variables must always start with a dollar symbol ($) followed by the variable name. For instance, $price=10; price is the variable name. 

The next rule is that all variable names should start with a letter or an underscore. And, variable names should only contain letters, numbers, or underscores. There should be no spaces and other characters. Lastly, PHP variables are case-sensitive. Hence, $SIZE is different from $size.

9. Discuss your experience in PHP development.

In my previous company, I created a portal for online customers. I programmed my PHP scripts to generate JavaScript when executed. Thus, I was able to access JavaScript by a browser.

I was able to create front-end features to help customers shop online in a reliable and cross-platform way.

10. How do you keep yourself updated?

I understand that PHP development is constantly changing, like everything else in the software development industry. I usually go to online forums to read about the latest developments. Also, I research new PHP development techniques and try them during my free time.

These are just the common PHP interview questions. Your hiring team can use the experience of your current PHP developers to come up with more specific questions that relate to your projects and other business needs.

How to Conduct the Interview

Companies have their take on the interview process. However, there are usually two types of interviews: Standard and Remote or Take-Home.

Standard Interview

This is the most common interview process. It starts with your recruiter or hiring manager calling the applicant. During the initial interview, your recruiter will check if they are interested in the job position. They will also gauge if the applicants are fit for the said position. Also, during this call, they will do a simple background check by asking applicants about themselves and job experiences.

If they pass the initial interview, your recruiters will then schedule them for both technical tests and interviews. The test will be there to check each candidate’s PHP aptitude in this field. Once done with the test, the developer candidates will have an interview with a senior PHP developer or a team leader from your organization.

Unlike the initial interview, your team will focus more on the candidates’ technical skills. Your hiring team should also ask applicants to perform specific and situational PHP developer tasks.

Lastly, your hiring team should invite the candidates for another in-house interview after passing the second stage. This will be their final interview. During this stage, once again, go over each job applicant’s portfolio and check if their skills fit your business needs.

Remote or Take-Home Interview

This type of interview is similar to the standard ones, except that they are done remotely. It has become more common due to social distancing restrictions brought about by the COVID pandemic.

First, the initial interview will be via phone call. After that, your hiring manager will give the job applicants a take-home PHP development exam. Some companies may set a timeframe to finish the assignment.

After the technical test, applicants should have an online interview. For the technical interview, form a panel composed of senior developers and a team leader. They will be in charge of checking the applicant’s qualifications through your prepared PHP interview questions.

Find the Best PHP Developers at Full Scale!

The competition in hiring the best software and web developers is getting tighter. This means it will be harder for you to recruit skilled and affordable talent. We have the solution to your problem.

We at Full Scale will take care of your talent problem. Our world-class recruitment process ensures that our PHP developers and other specialists are top of their fields. Plus, our training and mentorship programs help our developers to continue improving their skills. Contact us now and let’s start talking about your development needs!

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