A proxy communication system translates contact identifiers. The proxy communication system maps one or more client device contact identifiers to one or more proxy contact identifiers from a pool of proxy contact identifiers. The proxy communication system may facilitate communication on behalf of the client device using the proxy contact identifier. The proxy communication system may also communicate with the client device on behalf of the target device using the client device contact identifier. In some implementations, the mapping may be state dependent, such as different mappings based on a target device contact identifier, recent communications between the client device and the target device, and so on.