Those of us with an interest in Gemini (the small web protocol, not the AI thing) will have become familiar with CGI and its variants again, as they are commonly used to serve dynamic content over that protocol. Another variant is SCGI[0]. It doesn't seem to have ever been nearly as popular as FastCGI, but seems to be more commonly supported by Gemini servers due to its simplicity.

0: https://github.com/nascheme/scgi