This demo paper presents BeamArmor, an innovative real-time system aimed at monitoring and mitigating jamming attacks within cellular networks. Jamming attacks pose significant threats to normal network operations, causing disruptions in communication services and jeopardizing emergency situations. In this work, we emphasize the demonstration of BeamArmor through a realistic setup employing the srsRAN 5G cellular network stack in conjunction with USRP software-defined radios (SDRs) in an over-the-air wireless environment. We show that a jammer device close to the base station can bring the link down to an outage. The cellular link can be restored by turning on BeamArmor’s anti-jamming using MIMO null-steering. This demo provides valuable insights into the potential of BeamArmor as a reliable and efficient solution to counter jamming attacks in cellular networks.