LAMP is a solution stack of free, open source software. The acronym LAMP refers to the first letters of Linux (operating system), Apache HTTP Server, MySQL (database software), and PHP, Perl or Python, principal components to build a viable general purpose web server.
The exact combination of software included in a LAMP package may vary, especially with respect to the web scripting software, as Perl or Python are sometimes dropped from the stack. Similar terms exist for essentially the same software suite (AMP) running on other operating systems, such as Microsoft Windows (WAMP), Mac OS (MAMP), Solaris(SAMP), iSeries (iAMP), or OpenBSD (OAMP).
Though the original authors of these programs did not design them all to work specifically with each other, the development philosophy and tool sets are shared and were developed in close conjunction. The software combination has become popular because it is free of cost, open-source, and therefore easily adaptable, and because of the ubiquity of its components which are bundled with most current Linux distributions.
When used together, they form a solution stack of technologies that support application servers.
Like the other LAMP components, Linux is free open-source software which means the source code is available for the operating system, which can be edited according to specific needs.
MySQL is a multithreaded, multi-user, SQL database management system (DBMS) now owned by Oracle Corporation. Alternatives at this level of the stack do also exist, for example by using PostgreSQL (LAPP).
PHP, Perl, or Python
Variants and equivalents on other platforms
With the growing use of LAMP, variations and retronyms appeared for other combinations of operating system, web server, database, and software language. For example the equivalent installation on a Microsoft Windows operating system is known as WAMP. An alternative running IIS in place of Apache called WIMP. Variants involving other operating systems include MAMP (Macintosh), SAMP (Solaris), FAMP (FreeBSD) and iAMP (iSeries). The web server or database management system also vary. LEMP is a version where Apache has been replaced with the more lightweight web server Nginx. A version where MySQL has been replaced by PostgresSQL is called LAPP.
A server running LAMP may be colloquially known as a lamp box, punning on the type of post box. The GNU project is advocating people to use the term "GLAMP" since what is known as "Linux" includes the GNU tools as well as the Linux kernel