Lighttpd is built to be small. It also strives to give all the needed functionality for a variety of applications. As different users tend to have different needs, it is only logical that Lighttpd is extensible with modules. To keep this module small, the module interface is quite simple. Modules get the full benefit of the Lighttpd configuration file parser, so they do not need to create their own. This also keeps the configuration syntax for modules consistent.

Modules live directly in the server. They are usually written in C (Lighttpd requires a C binding, which could be done with C++ or other languages, but in practice rarely is), so they are faster than using mod_magnet (which is already pretty fast). The downside is that writing a module is much more tedious and error-prone than writing a Lua script for use with mod_magnet. This brings us to the following rule of thumb: