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Top 100 PHP Interview Questions & Answers (2026)
100 Questions
42 Beginner
34 Intermediate
24 Advanced
About PHP
PHP powers over 77% of all websites with a known server-side language, including WordPress (which runs 43% of the web), Facebook's original backend, Wikipedia, and countless SaaS products. Modern PHP 8.x is a mature, performant language with first-class named arguments, match expressions, fibers, enums, and readonly properties.
What to Expect in a PHP Interview
PHP interviews cover core language features, OOP, PHP 8.x improvements, security (SQL injection, XSS, CSRF prevention), performance optimization, Composer and dependency management, and framework knowledge. Laravel and WordPress roles add significant framework-specific depth.
How to Use This Guide
Start with core PHP questions before the OOP and security sections — interviewers often probe language fundamentals before framework specifics. The security section is critical for any PHP role since PHP's history makes security knowledge a strong differentiator.
Curated by Tech Baithak Editorial Team · Last updated: May 2026
Beginner
42 questions
Core concepts every PHP developer must know.
01
What is PHP?
02
What is the difference between echo and print in PHP?
03
What are PHP data types?
04
What is the difference between == and === in PHP?
05
What are PHP superglobals?
06
What is the difference between GET and POST methods in PHP?
07
What are sessions in PHP?
08
What are cookies in PHP?
09
What is a PHP array?
10
What is the difference between include and require in PHP?
11
What is a PHP function?
12
What is the difference between null, false, and empty string in PHP?
13
What are PHP string functions?
14
What are PHP array functions?
15
What is string interpolation in PHP?
16
What is the difference between intval(), floatval(), and strval()?
17
What are PHP date and time functions?
18
How do you connect to a MySQL database in PHP?
19
What are prepared statements and why are they important?
20
What is XSS and how do you prevent it in PHP?
21
What is SQL injection and how do you prevent it in PHP?
22
What is object-oriented programming (OOP) in PHP?
23
What is a PHP class and how do you create one?
24
What is the __construct() method in PHP?
25
What are PHP magic methods?
26
What is $this in PHP?
27
What is the difference between public, protected, and private in PHP?
28
What is inheritance in PHP?
29
What is an interface in PHP?
30
What is an abstract class in PHP?
31
What is a namespace in PHP?
32
What is Composer in PHP?
33
What is PSR in PHP?
34
What is the difference between array() and [] syntax in PHP?
35
What is type hinting in PHP?
36
What is the null coalescing operator in PHP?
37
What is the spaceship operator in PHP?
38
What are PHP closures (anonymous functions)?
39
What is PHP 7 and what major features did it introduce?
40
What is PHP 8 and what major features did it introduce?
41
What is the match expression in PHP 8?
42
What are named arguments in PHP 8?
Intermediate
34 questions
Practical knowledge for developers with hands-on experience.
01
What is a PHP trait?
02
What is the nullsafe operator in PHP 8?
03
What are PHP 8.1 enums?
04
What are readonly properties in PHP 8.1?
05
What is PHP Fibers?
06
What is the static keyword in PHP?
07
What is late static binding in PHP?
08
What is PHP error handling and exception handling?
09
What is PDO in PHP?
10
What is the difference between array_map, array_filter, and array_reduce?
11
What is dependency injection in PHP?
12
What is the Iterator interface in PHP?
13
What are PHP generators?
14
What is PHP's Autoloading?
15
What is CSRF and how do you prevent it in PHP?
16
What is the difference between include_once and require_once?
17
How does PHP handle file uploads?
18
What is output buffering in PHP?
19
What is the SPL (Standard PHP Library)?
20
What is the ArrayAccess interface in PHP?
21
What is Guzzle HTTP Client in PHP?
22
What is Symfony and Laravel?
23
What is an ORM and how does Eloquent work?
24
What is declare(strict_types=1) in PHP?
25
What is the difference between PDO and MySQLi?
26
What is a Service Container (IoC Container) in PHP?
27
What is Redis and how is it used in PHP?
28
What is PHP's arrow function and how does it differ from a closure?
29
What is PHP's Countable interface?
30
What is PHP session security best practices?
31
What is the difference between abstract methods and interface methods in PHP?
32
What is the Adapter pattern in PHP?
33
What is the Facade pattern in PHP/Laravel?
34
What is the difference between method chaining and fluent interface?
Advanced
24 questions
Deep expertise questions for senior and lead roles.
01
What is PHP's Just-In-Time (JIT) compiler?
02
What is OPcache in PHP?
03
What is PHP-FPM?
04
What is Reflection in PHP?
05
What are PHP Attributes?
06
What is PHP's garbage collection mechanism?
07
What is PHP's memory management and how to optimize it?
08
What is the Decorator pattern in PHP?
09
What is the Repository pattern in PHP?
10
What is SOLID in PHP?
11
What is middleware in PHP frameworks?
12
What is event-driven programming in PHP?
13
What is Command Query Responsibility Segregation (CQRS) in PHP?
14
What is PHP async programming with ReactPHP or Amp?
15
What is Domain-Driven Design (DDD) in PHP?
16
What are intersection types in PHP 8.1?
17
What is PHP profiling and how do you use Xdebug?
18
What is PHP FFI (Foreign Function Interface)?
19
What is the Proxy pattern in PHP?
20
What is immutability and value objects in PHP?
21
What is PHP's SPL data structures vs native arrays?
22
What is the PHP Event Loop concept with ReactPHP?
23
What is the Command pattern and command bus in PHP?
24
What are PHP design patterns for solving common problems?
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100 questions total