PHP Engine creates a logical object to preserve data across subsequent HTTP requests, which is known as session.

Sessions generally store temporary data to allow multiple PHP pages to offer a complete functional transaction for the same user.

Simply, it maintains data of an user (browser).

In PHP, a session refers to a way to preserve data across subsequent HTTP requests. It enables you to store user-specific information and persist it throughout the user’s interaction with your website or web application.

Here’s a breakdown of how sessions work in PHP:

Session Initialization: When a session starts, PHP generates a unique identifier called the session ID, which is usually stored in a cookie on the user’s browser. If cookies are disabled, PHP appends the session ID to URLs.
Data Storage: Once a session is initiated, you can store data in the $_SESSION superglobal array. This array persists throughout the user’s session, allowing you to store and retrieve information as needed.
Session Management: PHP provides functions to manage sessions, such as session_start() to initialize a session, session_destroy() to terminate a session, and session_unset() to unset all session variables.
Session Security: It’s essential to ensure session security to prevent unauthorized access and session hijacking. Techniques like using HTTPS, regenerating session IDs, and validating user inputs can enhance session security.
Session Expiration: Sessions can be configured to expire after a specified period of inactivity or based on other criteria. This helps manage server resources and improve security by preventing stale sessions.

In summary, a session in PHP is a mechanism for preserving user-specific data across multiple page requests during a user’s interaction with a website or web application. It allows developers to create personalized experiences and maintain stateful interactions with users.