Commonwealth Fusion Systems develops fusion energy systems using high-temperature superconducting (HTS) magnets to create compact tokamak reactors. It is building SPARC, a demonstration device designed to achieve net energy gain from fusion and laying the groundwork for ARC, a grid-connected fusion power plant targeting early 2030s operation. The company partners with MIT and manufactures its HTS magnets and related components, applying peer-reviewed science in its firewalling of plasma and reactor engineering. It has introduced innovations like the PIT VIPER superconducting cable to support pulsed-power magnet systems and accelerate readiness for commercial fusion.