lighttpd is a secure, fast, compliant, and very flexible Web server which has been optimized for high-performance environments. It has a very low memory footprint compared to other Web servers, and it takes care of CPU load. It has an advanced feature set that includes FastCGI (load balanced), CGI, Auth, Output-Compression, URL-Rewriting, SSL, and much more.
spawn-fcgi is a little helper program to spawn fastcgi processes. It binds them to a socket (either Unix-domain or TCP) and configures the environment by switching the user and group, using chroot, daemonizing, and using chmod and chown on Unix-domain sockets. The spawned backends can then be used from Web servers like lighttpd, nginx, or cherokee.