The acronym LAMP refers to a set of free software programs commonly used together to run dynamic Web sites or servers Linux, the operating system; Apache, the Web server; MySQL, the database management system (or database server) and Perl, PHP, and/or Python, scripting languages. The LAMP stack is a very popular setup and many websites run on it. Best of all, all four of the tools in the stack are free and open source and really easy to get started with.