Colorize is an application for colorizing chunks of code in several programming languages. It is the same colorizing engine as lisppaste made standalone. It's licensed under the MIT license, written by Brian Mastenbrook, and currently maintained by Brit Butler. It requires html-encode, split-sequence, and alexandria.

The source and up to date docs may be found on github.

This is an interesting example that acts like a server-side include of colorized Lisp code for HTML.

Quick assessment (2023-02-27)

(COLORIZE:COLORIZE-FILE :C "C:/mdbm/src/lib/mdbm.c")
took 42,242,000 microseconds (42.242000 seconds) to run.
        174,595 microseconds ( 0.174595 seconds, 0.41%) of which was spent in GC.
During that period, and with 4 available CPU cores,
     20,015,625 microseconds (20.015625 seconds) were spent in user mode
         93,750 microseconds ( 0.093750 seconds) were spent in system mode
 283,678,896 bytes of memory allocated.

The file is 9,816 lines, so that works out to about 232 lines per second.