The sole purpose of DPP Proxy is to allow desktop wallets to receive incoming payments without needing to expose a web host to the internet from their local machine.
The Proxy sits on the open internet ready to receive incoming payment requests on users' behalf. When such a request comes in, the message is routed to the appropriate client wallet.
Usually DPP Proxy is set up in
hybridmode. This means the incoming requests are https, but the client connection is done over secure web socket.
It is possible to configure DPP Proxy as entirely
http, which means the transports on both sides of the proxy would be either socket or http endpoints.