When you host a website using PHP, a PHP handler is the software component that processes PHP code on the server. It acts as a bridge between the web server (like Apache or Nginx) and the PHP interpreter, executing your scripts to generate dynamic web pages.

Choosing the right handler impacts your site's performance, stability, and compatibility. Common handlers include:

• mod_php (for Apache): Integrated directly, simple but uses more memory per process.
• CGI/FastCGI: Runs PHP as separate processes; more flexible and secure.
• PHP-FPM (FastCGI Process Manager): Modern, efficient handler with advanced features like adaptive process spawning.

For most users on shared hosting, the handler is pre-configured. However, if you manage your server or use VPS hosting, selecting an optimal handler is key. PHP-FPM is often recommended for its speed and resource management, especially with Nginx.

To check your current handler, you can create a PHP file with <?php phpinfo(); ?> and look for the "Server API" entry. If you need to change it, consult your hosting provider or server administrator, as improper configuration can cause site errors.

In summary, a PHP handler is a crucial backend element that ensures your PHP-based website runs smoothly. Understanding its role helps you make informed decisions about hosting and performance optimization.