A free and portable Common Lisp Webserver.
Portable AllegroServe is a variant of AllegroServe(tm) with an explicit emphasis on portability between Lispsystems and Operating Systems. You can find the original AllegroServe at https://github.com/franzinc/aserve
The best way to install Portable AllegroServe is through Quicklisp (http://quicklisp.org/). (The best way to install any Lisp library is through Quicklisp.)
portableaserve is small and works nicely
I used portableaserve to build a web interface to my Lisp scripts for compiling and building the C code I must maintain at work. I have now a web site that has a compile button on it that I can push from any computer. I also used portableaserve as a web client library, so that my web interface also provides buttons to send pre-scripted http: requests to _other_ computers to do things with those computers (like upload/download my compiled code and reboot). I did not implement the servers on the other computers but took advantage of features they already presented via web pages. Also I do some regular web page serving, since it's such a snap.
portableaserve is a solid, trusty Common Lisp webserver with a long history, and it provides a crucial component which allowed us to port our GenDL (Genworks-GDL) system to LispWorks, SBCL, and CCL (the lead platform continues to be Allegro CL and uses Allegro's native aserve). Note that portableaserve is now available through Quicklisp as the :aserve system. For additional platforms, it will be very nice to see portableaserve extended to support ABCL and ECL next!