Editing Portal:SaaS and Web Development (section)

=== FastCGI and persistent processes ===

Another response to CGI’s performance problem was '''FastCGI'''. FastCGI kept application processes running across multiple requests instead of starting a new process for every request. This allowed applications to reuse memory, cached data, and database connections while remaining separate from the web server process.

FastCGI was not Perl-specific, but Perl applications could use it. It occupied a middle ground between traditional CGI and embedded server modules such as mod_perl or mod_php. With FastCGI, an application could be persistent without being embedded directly inside Apache.

This separation became especially important for shared hosting and multi-user systems. Embedded interpreters were fast, but they could complicate isolation between users and applications. FastCGI-style deployment made it easier to run applications as separate users or services.

FastCGI also helped prepare the way for later deployment models where the web server acts as a front end and application processes run separately behind it.