Privoxy vs Zen

Privoxy is free, non-caching web proxy software for privacy controls, access rules, and changes to HTTP headers and web pages. It can modify page text, remove banners and web bugs, filter HTML annoyances, and inspect HTTPS requests and responses. A browser-based configuration and control utility includes rule tracing and remote toggling, and Privoxy can be chained with other proxies. It can serve multiple clients across a network or as a LAN gateway. The software runs on Windows, GNU/Linux, Mac OS X, Haiku, BSD variants, Solaris, and other Unix systems. It is licensed under the GNU GPL version 2 or later, with a free plan listed at free. A basic configuration is included with a new installation, but many advanced features need to be enabled. Privoxy handles HTTP and HTTPS proxying; it does not handle FTP, SMTP, instant messaging, IRC, or ICQ. It is not designed as a malware-removal tool, and the default setup does not filter malware. The project says it lacks trusted build infrastructure; individual project members or external contributors build and upload binary packages.

Zen has no write-up on Specifiction yet; its figures are above.