Citadel Core

Cross platform filtering HTTP/S proxy based on .NET Standard 2.0.

This is the open source version of our filtering proxy. It is now in a feature freeze, and will only receive bug fix patches. Development continues privately at Technik Empire.

If you have a commercial interest in this software, my condolences. I will not support you in it. A few people have tried, only to realize their business plan, which is based solely on copying and pasting my work and waking up in a pile of money, doesn't actually pan out. Turns out they didn't have a clue ("internet, like how does it work?") and then come crying to me when reality hits. If you're qualified, you'll never ask me anyway, in which case, all the best to you.

CitadelCore supports proxying of both HTTP/S and Websocket (Ws/Wss) connections. As of v1.4.2, CitadelCore's Websocket proxy passes the Autobahn Test Suite.

Note that CitadelCore is an abstract library by design. Since the proxy is designed to be run as a local, transparent filtering proxy, a platform-specific mechanism for diverting traffic back into the proxy must be implemented on each platform. All other logic is implemented in this library.

In short, that means this library bundles a full-fledged, compliant HTTP/S web server and has handlers that bridge (aka proxy) those webserver requests to the real upstream target. At various stages of transactions in that pipline, exposed callbacks are invoked enabling users to perform deep content inspection, connection filtering, and content modification.

For the Windows specific implementation, please see CitadelCore.Windows.