Funny to reflect that there was a time not so long ago when writing web apps (CGI usually) in C wasn't at all unusual (shortly before Perl became much more popular for this). And today, it is indeed kind of crazy.
Depends on your definition of "not so long ago" - it's certainly most of the history of the web. The point when Perl, PHP, and Java started to become the dominant web app technologies is about as far from the present day as that point was from the moon landing.
I remember writing CGI scripts in Perl in 1993 ( the year before Netscape ). I am not sure when CGI even became a thing but it could not have been long before that.
Not only was “not so long ago” kind of at the very beginning of meaningful web history but it was also for a very brief moment in time ( if we are talking pre-Perl ). Pre-Perl CGI may have never been a thing though as Perl is older than CGI.
I recall PHP being the next wave after Perl. One could argue it never lost its place even if it now has many neighbours.
Not a Perl advocate by the way though it did generate some pretty magical “dynamic” web pages from text files and directory listings back in the day. Similar story with PHP.
It is true the time when it might have been sane to write CGI in C was very brief. Perl took over almost immediately (and to my chagrin, eventually PHP ate Perl's lunch). I remember reading CGI books that would explain how to do it in either Perl or C, the justification being "in case you need C for performance" but in reality I don't think a ton of C CGI was written. There was definitely some though; I recall poking around in cgi-bin directories and finding some compiled executables (could have been another compiled language like C++) and being disappointed I couldn't view the source like with .pl files.
It really takes you back to a very specific point in time though. A magical time when every year or month software and internet technology would take big leaps and bounds. When you might do things in a way that is very manual and slow compared to today and yet it was amazing at the time.
I remember learning CGI to write a web app in late 90s. Most resources at the time seemed to focus on it as a Perl thing, with all code examples etc being in Perl, other languages mentioned briefly if at all (usually at the beginning, when explaining the "it's just a process" model).