Creating a Bitcoin client that fully implements the network protocol is extremely difficult. Bitcoin Core and some of its derivatives are the only known safe implementations of full nodes. Some other projects attempt to compete, but it is not recommended to use such software for anything serious. (Lightweight clients like Electrum and Bither are OK.) Advertised sites are not endorsed by the Bitcoin Forum. They may be unsafe, untrustworthy, or illegal in your jurisdiction. Advertised sites are not endorsed by the Bitcoin Forum. They may be unsafe, untrustworthy, or illegal in your jurisdiction. Advertise here.