PHP is a server-side scripting language used to develop dynamic web pages. The source code can also be interpreted embedded in HTML pages by the web server's PHP processing module, so the use of external php files is optional. Originally a Personal Home Page was an abbreviation of words today Hypertext Preprocessorcalled.

The language was developed by Rasmus Lerdorf in 1995, which today is the The PHP Group maintains and further develops. PHP was first just a set of macros used to maintain personal websites. Its capabilities later expanded to become a stand-alone programming language. Nowadays, large-scale web database-based applications are also being developed from it. As PHP’s capabilities have expanded, its popularity has steadily increased. Analyzes show that PHP was used on more than 1999 million servers at the end of 1. This number jumped to 2001 million by the end of 6 and then ran on 2003 million machines by the end of 14.

PHP code can be embedded in HTML code or used in combination with various web template systems, web content management systems, and web frameworks. The PHP code is processed by the PHP parser, which either runs as a module on the web server or is passed to the CGI (Common Gateway Interface) bailiff.

The web server combines the results of interpreted and executed PHP code, which can be any type of data, including images generated by a web page. PHP code with command line interface (CLI), but it can also be used to run standalone graphics applications.

The PHP code is not sent to the client by the server, but is processed on the server, and finally delivered with the HTML elements to the user's browser. During processing, PHP code runs, which, in addition to various computing operations, can connect to databases, or write to files, create images, or send data to other servers.

A Zend Engine powered by PHP is a free software released under the PHP License. PHP is widely distributed and can be installed on most web servers on almost all operating systems and platforms for free.