In this paper we present a new peer-to-peer (P2P) middleware called CHEap Distributed ARchitecture (Chedar). Chedar is totally decentralized and can be used as a basis for P2P applications. Chedar tries to continuously optimize its overlay network topology for maximum performance. Currently Chedar combines four different topology management algorithms and provides functionality to monitor how the peer-topeer network is self-organizing. It also contains basic search algorithms for P2P resource discovery. Chedar has been used for building a data fusion prototype and a P2PDisCo distributed computing application, which provides an interface for distributing the computation of Java applications. To allow Chedar to be used in mobile devices, the Mobile Chedar middleware has also been developed.