On the defence side, 21strategies developed the Defense Metaverse, a simulation environment that creates AI-based red teaming and tactical training for armed forces. The original GhostPlay project (2021–2024), co-developed with HENSOLDT and funded by dtec.bw, established the first comprehensive AI red teaming capability for military systems. In 2025 the company became main technical contractor for GhostPlay@SEA, an EU NextGenerationEU-funded follow-on project applying tactical AI and adversarial simulation to naval unmanned systems, with ATLAS Elektronik and Rheinmetall Defence Electronics among the consortium partners.

For industry, flow21 is a separate platform that applies the same reinforcement learning core to manufacturing production flows, helping factories manage volatile supply chains, anticipate bottlenecks and reduce lead times. The company positions this as economic preparedness — supply chain resilience as a defence-adjacent capability.

HENSOLDT, Europe's largest independent sensor technology company, took an initial minority stake in 21strategies in January 2023 and increased that stake in July 2025. In November 2025 the company signed a letter of intent with Polish firm APS Energia to develop intelligent next-generation drone systems. 21strategies participates regularly in major defence forums including AFCEA Bonn and NATO exercises such as REPMUS 2025, where it demonstrated tactical swarm behaviour using robotic dog platforms.