Frequently asked PHP questions

The following collection is a community driven project of qualified and unbiased answers to the most frequently asked questions about PHP.

Introduction to PHP

• What is PHP? Where should I start?
• Why choosing PHP?
• Which books are recommended for learning PHP?
• Which hosting service should I use for PHP, are there any free hosting providers?
• Why does PHP use a dollar sign $ to prefix variables?
• PHP 7
• What is the difference between a core and vanilla developer?

Databases

• Why are mysql_* functions removed and what to do?
• PDO vs. mysqli?
• How to store files in a database?
• MongoDB vs. MySQL
• What is ORM?

Security

• How to secure PHP web applications and prevent attacks?
• How to work with users’ passwords and how to securely hash passwords in PHP?
• What is SQL injection and how to prevent it?
• How to securely upload files with PHP?
• How to protect and hide PHP source code?
• How to install SSL certificate and enable HTTPS?

PHP frameworks

• What is a PHP framework and which one should I learn and use?
• How to make your own PHP framework?

Code quality and testing

• How to test PHP code?
• How to debug PHP code?

Packages, libraries and managing dependencies

• Where to find open source PHP libraries, scripts and packages?
• What is Composer?
• What is CMS and which one should I use?
• Which eCommerce application should I use or which framework to use for building eCommerce application?
• How to work with Excel in PHP?
• Are there any image manipulation libraries in PHP? Which ones are good?
• How to add pagination?
• What is payment gateway? How to integrate and use payment gateways in PHP?
• How to work with PDF files in PHP?

Interoperability

• Which editor and IDE to choose for writing PHP code?

Miscellaneous PHP questions

• How to use Google operators?
• How to detect browser in PHP?
• Where to get PHP certification?
• What is web crawling and how to crawl websites with PHP?
• Can PHP be used for building desktop applications?
• How to send email with PHP?
• How to detect face with PHP?
• $_GET vs $_POST?
• How to fix “Cannot modify header information - headers already sent by…” warning?
• How to increase the file upload size in PHP?
• How to get client’s IP address in PHP?
• How to detect ISP with PHP?
• How to make readable, SEO friendly URLs in PHP?
• What is the difference between a developer and programmer?
• Can you suggest some projects I can make?
• What is web scraping and how to scrape data in PHP?
• How to take screenshot of a URL with PHP?
• Single vs double quotes in PHP
• How to send SMS with PHP?
• Which PHP template engine to use?
• Undefined variable/index notice
• How to fix failed to open stream warning?
• How to manage wildcard subdomains in PHP?
• How to choose a PHP project directory structure?
• How to bring variables into a method, the right way