Top 10 PHP Interview Questions and Answers (2025 Updated)
Top 10 PHP Interview Questions and Answers (2025 Updated)
Top 10 PHP Interview Questions and Answers (2025 Updated)
Preparing for a PHP interview in 2025? Whether you are a fresher, experienced developer, or aiming for a Laravel/PHP job, these top PHP interview questions with answers will help you. We cover PHP basics, OOP concepts, SQL injection prevention, PHP 8 features, and more.
1. What is PHP and Why is it Used? [Beginner]
Answer: PHP (Hypertext Preprocessor) is an open-source server-side scripting language mainly used for web development. It allows developers to build dynamic and interactive websites, and it integrates easily with databases like MySQL. PHP is widely popular because it is free, easy to learn, and supported by almost all hosting providers.
2. Difference Between GET and POST in PHP [Basic]
Answer: The GET method sends form data through the URL, making it visible and less secure. It has a length limitation but is useful for bookmarking. The POST method sends data through the HTTP request body, making it secure and without size restrictions. POST is recommended for sensitive data like login forms.
3. PHP Sessions vs Cookies [Important]
Answer: A Session stores user information on the server and is unique to each user. It ends when the browser is closed or after a timeout. A Cookie stores small pieces of information in the client’s browser and can persist even after the browser is closed. Sessions are more secure, while cookies are useful for remembering user preferences.
4. Explain MVC Architecture in PHP (Laravel Example)
Answer: MVC stands for Model-View-Controller.
- Model: Handles database logic (e.g., Laravel Eloquent models).
- View: Represents the presentation layer (HTML, Blade templates).
- Controller: Acts as a middleman, processing requests and sending data between model and view.
This architecture makes PHP applications more organized and scalable.
5. include() vs require() vs include_once() vs require_once()
Answer:
- include(): Generates a warning if the file is missing but continues execution.
- require(): Generates a fatal error if the file is missing, stopping execution.
- include_once(): Same as include, but prevents multiple inclusions of the same file.
- require_once(): Same as require, but avoids multiple inclusions.
Using require_once() is the safest for critical files like configuration files.
6. PDO vs MySQLi in PHP [Advanced]
Answer:
- MySQLi: Works only with MySQL databases and supports both procedural and OOP style.
- PDO (PHP Data Objects): Works with multiple databases (MySQL, PostgreSQL, SQLite, etc.). It provides a uniform API and supports advanced features like prepared statements, making it more secure against SQL injection.
For scalable applications, PDO is recommended.
7. PHP OOP Concepts Explained (Encapsulation, Inheritance...)
Answer: PHP supports Object-Oriented Programming (OOP) concepts:
- Encapsulation: Bundling variables and methods in a class.
- Inheritance: A class can inherit properties and methods from another class.
- Polymorphism: The ability of a function/method to behave differently based on context.
- Abstraction: Hiding implementation details and exposing only essential features.
These concepts make PHP code more reusable and maintainable.
8. PHP 7 vs PHP 8 Features [Latest]
Answer:
- PHP 7: Introduced performance improvements, scalar type hints, error handling, and null coalescing operator.
- PHP 8: Introduced JIT compiler for faster execution, union types, named arguments, match expressions, and attributes.
Upgrading to PHP 8 ensures better performance and access to modern features.
9. Preventing SQL Injection in PHP [Security]
Answer: SQL Injection can be prevented by using Prepared Statements with PDO or MySQLi. Always validate and sanitize user input before inserting into the database. Avoid directly concatenating user input into queries. Using frameworks like Laravel further reduces risks with built-in ORM protection.
10. Composer and Autoloading in PHP [Modern PHP]
Answer: Composer is the dependency manager for PHP. It allows developers to install and manage external libraries easily. Autoloading automatically loads PHP classes when they are needed, without requiring manual include/require statements. Together, these features simplify development and support modern PHP practices.
