Editing Portal:SaaS and Web Development (section)

=== CGI and the first dynamic websites ===

In the earliest web era, CGI was simple and powerful. A web server such as Apache could receive a request, set environment variables, pass input to a program, and return whatever that program printed. The program could be written in many languages, but Perl quickly became one of the most common choices.

Perl fit CGI because CGI itself was text-oriented. HTTP headers, form data, query strings, cookies, and HTML were all text. Perl was already strong at reading environment variables, parsing strings, escaping output, handling files, and generating reports. A Perl CGI script could be written quickly and deployed by copying it into a `cgi-bin` directory.

This made Perl one of the first practical languages of web application development. Perl CGI scripts powered early search forms, site counters, feedback forms, mailing-list tools, file upload systems, shopping carts, webmail interfaces, bulletin boards, bug trackers, intranets, and administrative panels.

The CGI model had a major limitation: a new process was typically started for every request. That made CGI easy to understand and isolate, but inefficient under heavier traffic. Each request could require starting Perl, loading modules, connecting to a database, generating a response, and then exiting. For small sites this was acceptable. For busy sites, it became expensive.