Linux, BSDs and all other UNIX-like systems, PostgreSQL, Redis, Nginx, HAProxy, interpreters of Python and many other languages, tons of libraries, ... and the

Linux, BSDs and all other UNIX-like systems, PostgreSQL, Redis, Nginx, HAProxy, interpreters of Python and many other languages, tons of libraries, ... and the list could go on and go on. A lot of very successful and robust software is written in C. The preference for the C language is certainly not due to a personal opinion of only one person.