# PHP Developer Interview Questions

By Dinesh Uprety
Published: 2024-12-21
Updated: 2024-12-21
Canonical: https://laranepal.com/blog/php-developer-interview-questions

# PHP Developer Interview Questions

This article provides a list of questions designed to assess a PHP developer’s skills in areas like string manipulation,
debugging, database handling, and advanced PHP features.

1. **What is PHP? Why is PHP a Loosely Typed Language? Is PHP Asynchronous or Synchronous?**

2. **What is the difference between `include`, `require`, `include_once`, and `require_once`?**

3. **Identify the Issues in the Query Below**

    ```php
    "SELECT * FROM users WHERE email = $_POST['email']";
    ```

4. **Fix the Logical Error in the Statement**

    ```php
    if (!strpos($string, $substring))
    ```

5. **What is the Value of $x and $y After the Function Call?**

    ```php
    function incrementCounter(&$counter) {
        $initialValue = $counter;
        $counter += 2;
        return $initialValue;
    }
    
    $x = 5;
    $y = incrementCounter($x);
    ```

6. **Predict the Output of the Following Code and Explain Why?**

    ```php
    $num = 10;
    function modifyNumber() {
        $num = 20;
    }
    modifyNumber();
    echo $num;
    ```

7. **Predict the Value of $x and Why?**

    ```php
    $octalValue = 017;
    $x = $octalValue / 2;
    ```

8. **What Will Be the Output?**

    ```php
    $method = "greet";
    function greet() {
        echo "Hello, world!";
    }
    $method();
    ```

9. **Explain `$$var` and Its Use Case in PHP. Can It Go Infinitely or Not?**

10. **Describe Magic Methods in PHP**

11. **Logical String Manipulation Question**

    Write a PHP function that takes a string and:
    - Reverses it.
    - Replaces all vowels (a, e, i, o, u) with their uppercase equivalent.
    - Replaces all consonants with #.

    Example:

    ```php
    Input: "helloWorld"
    Output: "DLROw#O###"
    ```

12. **Predict the Output of the Code Below and Explain Why?**

    ```php
    $name = "Sunita";
    echo "Hi, my name is {$name}";
    echo 'Hi, my name is {$name}';
    ```