Wikipedia
Tinyproxy
Tinyproxy is a HTTP proxy server daemon for POSIX operating systems. Designed to be fast and small, it is useful when an HTTP/HTTPS proxy is required, but the system resources for a larger proxy are unavailable. Because of this it has been put to uses such as a tether on the iPhone, and on the OpenWrt.
Tinyproxy is primarily designed to run on Unix-like systems. Released under the GNU General Public License, Tinyproxy is free software and has been developed for a number of years. It is currently being maintained on GitHub as a publicly accessible project. Ohloh analyses it to be a project with "mature, well-established codebase and increasing year-over-year development activity."