The document provides an overview of the eXperimental Infrastructures for the Future Internet (XIFI) project. XIFI aims to (1) support experiments on the Future Internet Public Private Partnership (FI-PPP) Core Platform by deploying its Generic Enablers across a federation of infrastructure nodes, (2) support FI-PPP use cases by allowing them to deploy applications at large scale, and (3) foster collaboration between the FI-PPP program and other initiatives. The document outlines XIFI's objectives, approach, technical architecture, services, timeline and open call for additional infrastructure nodes to join the federation.