The orchestration of network services is a well investigated problem. Standards and recommendation have been produced by ETSI and IETF while a significant body of scientific literature can be found exploring both the theoretical and practical aspects of the problem. Likewise several open–source as well as proprietary tools for network service orchestration are already available. Nevertheless, in most of these cases network services can only be provisioned across a single administrative domain effectively preventing end–to–end network service delivery across multiple Infrastructure Providers (InP). In this paper we present X–MANO, a cross–domain network service orchestration framework consisting in an inter–domain confidentially–presenting federation interface and in an information model for multi– domain network service life–cycle programmability. X–MANO is effectively deployment–agnostic and can be used in hierarchical, peer–to–peer and cascading (or recursive) configuration. We validate X–MANO trough a proof–of–concept implementation over a multi–domain testbed. Finally, we release all the code under a permissive APACHE 2.0 license making it available to researchers and practitioners.