PHP Developers are responsible for building and maintaining server-side web application logic using PHP. They often work with databases, APIs, and front-end technologies to create dynamic websites and applications. The following PHP Developer Interview Questions and Answers will help you prepare effectively.

Q1. What is PHP?

PHP is a popular open-source server-side scripting language used to create dynamic web pages and applications.

Q2. What are the main features of PHP?

PHP supports cross-platform compatibility, is open-source, has built-in database support, and supports a wide range of web servers and protocols.

Q3. What is the difference between echo and print in PHP?

Both are used to output data, but echo can take multiple parameters and has no return value, while print takes one argument and returns 1.

Q4. What are PHP data types?

Common PHP data types include integer, float, string, boolean, array, object, NULL, and resource.

Q5. How does PHP handle error reporting?

PHP uses error reporting levels like E_NOTICE, E_WARNING, E_ERROR, and you can configure error reporting using error_reporting() function and php.ini settings.

Q6. What is a session in PHP?

A session stores user information across multiple pages on a website using a unique session ID, maintained on the server.

Q7. What is the difference between GET and POST methods?

GET sends data via URL and is limited in size, visible, and less secure. POST sends data in the request body, not visible, and suitable for sensitive data.

Q8. How do you connect to a MySQL database using PHP?

Using the mysqli or PDO extension, by providing hostname, username, password, and database name to establish a connection.

Q9. What are prepared statements?

Prepared statements are used to execute the same SQL statements repeatedly with high efficiency and protect against SQL injection.

Q10. What is the difference between include and require?

Both include files, but require causes a fatal error and stops script execution if the file is missing, whereas include only raises a warning and continues.

Q11. What are traits in PHP?

Traits are a mechanism for code reuse in single inheritance languages like PHP to include methods in multiple classes.

Q12. How do you handle exceptions in PHP?

Using try, catch, and finally blocks to catch exceptions and handle errors gracefully.

Q13. What is the use of the PHP function isset()?

isset() checks if a variable is set and is not NULL.

Q14. What is the difference between == and === in PHP?

== compares values after type juggling, === compares both value and type strictly.

Q15. What is a cookie in PHP?

A cookie is a small piece of data stored on the client-side used to track user information across sessions.

Q16. How do you upload a file in PHP?

By using an HTML form with enctype=”multipart/form-data” and handling the uploaded file using the $_FILES superglobal.

Q17. What are magic methods in PHP?

Magic methods are special methods like __construct(), __destruct(), __get(), __set() that provide specific behaviors in classes.

Q18. How do you prevent SQL injection in PHP?

Use prepared statements with bound parameters, validate and sanitize user inputs.

Q19. What is the difference between a class and an object?

A class is a blueprint for objects; an object is an instance of a class.

Q20. What is namespace in PHP?

Namespaces organize code and avoid name collisions between classes, functions, or constants.

Q21. How do you start a session in PHP?

By calling session_start() at the beginning of the script before any output.

Q22. What is the difference between static and instance methods?

Static methods belong to the class and can be called without creating an object, instance methods belong to an object instance.

Q23. How can you send an email using PHP?

Using the mail() function, providing recipient, subject, message, and headers.

Q24. What are the different types of errors in PHP?

Parse errors, fatal errors, warning errors, and notice errors.

Q25. How do you handle file operations in PHP?

Using functions like fopen(), fread(), fwrite(), fclose(), and file_get_contents() for reading and writing files.