PHP Interview Questions & Answers

🚀 PHP Interview Preparation – Crack Your Next PHP Job Interview

Getting ready for a PHP developer interview? No worries! We’ve compiled a list of essential PHP interview questions to help you prepare for both beginner and advanced roles. 💡

📝 Basic PHP Interview Questions

✅ 1. What is PHP?

Answer: PHP stands for Hypertext Preprocessor. It is a server-side scripting language used for web development.

✅ 2. What are the key features of PHP?

Answer: PHP is:

  • ✅ Open-source and free
  • ✅ Server-side and fast
  • ✅ Supports databases like MySQL, PostgreSQL
  • ✅ Has built-in security functions
  • ✅ Works well with HTML and JavaScript

✅ 3. What is the difference between echo and print in PHP?

Answer:

  • echo → Faster, can print multiple values.
  • print → Slower, always returns 1, used in expressions.

✅ 4. How do you declare a variable in PHP?

Answer: Variables in PHP start with $ and do not require a data type.

<?php
$name = "John"; // String
$age = 25; // Integer
?>

Try It Now

📝 PHP Functions & Loops Questions

✅ 5. What are PHP functions?

Answer: A function in PHP is a reusable block of code.

✅ 6. Write a function to check if a number is even.

<?php
function isEven($num) {
    return $num % 2 == 0;
}

echo isEven(10) ? "Even" : "Odd"; // Output: Even
?>

Try It Now

✅ 7. What is the difference between for and foreach?

Answer:

  • for → Used for iterating with a counter.
  • foreach → Used for iterating through arrays.

📝 Object-Oriented PHP (OOP) Questions

✅ 8. What are PHP classes and objects?

Answer: A class is a blueprint, and an object is an instance of a class.

<?php
class Car {
    public $brand;
    function __construct($brand) {
        $this->brand = $brand;
    }
}

$myCar = new Car("Toyota");
echo $myCar->brand; // Output: Toyota
?>

Try It Now

✅ 9. What are access modifiers in PHP?

Answer:

  • public → Can be accessed anywhere.
  • private → Can only be accessed within the class.
  • protected → Can be accessed in the class and child classes.

📝 PHP Security Questions

✅ 10. How to prevent SQL injection in PHP?

Answer: Use prepared statements and parameterized queries.

<?php
$conn = new mysqli("localhost", "root", "", "test");

$stmt = $conn->prepare("SELECT * FROM users WHERE email = ?");
$stmt->bind_param("s", $email);
$stmt->execute();
?>

Try It Now

✅ 11. How to prevent Cross-Site Scripting (XSS)?

Answer: Use htmlspecialchars() to sanitize user input.

📝 PHP Database Questions

✅ 12. How do you connect to MySQL using PHP?

<?php
$conn = new mysqli("localhost", "root", "", "test");
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}
echo "Connected successfully!";
?>

Try It Now

✅ 13. What is the difference between MySQLi and PDO?

Answer:

  • ✅ MySQLi → Supports MySQL only, procedural & OOP.
  • ✅ PDO → Supports multiple databases, only OOP.

🎯 More Interview Questions!

  • 🔹 Explain GET vs. POST requests.
  • 🔹 How does session handling work in PHP?
  • 🔹 What are PHP traits and when to use them?
  • 🔹 Explain the difference between abstract classes and interfaces.

💡 Tip: Practice coding these examples to be fully prepared for your interview! 🚀