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A Reverse Proxy is a simple way of saying a traffic forwarder. I get a request send from a client, send that request to another server, receive a response from the server and forward it back to the client. The reverse part of this simply means the proxy itself determines where to send traffic and when. If the proxy domain is equal to A send traffic to URL 1 or B to the Default URL. The concept is so simple it can be applied to assist in many different cases: Load balancing, A/B Testing, Caching, Authentication etc…