Genesis is a universal physics engine designed for robotics and physical AI simulation. It provides a unified multi-physics framework supporting rigid-body dynamics, finite element method (FEM), material point method (MPM), position-based dynamics (PBD), smoothed particle hydrodynamics (SPH), and incremental potential contact (IPC) coupling. The engine is GPU-accelerated via a custom compiler (Quadrants, forked from Taichi) and scales from single-CPU laptops to multi-GPU datacenters. It features differentiable simulation with gradient tape and manual backward passes, enabling end-to-end optimization through physics. The architecture follows a scene-entity-solver pattern with pydantic-based options for configuration, a plugin-based sensor system (cameras, IMU, tactile, lidar, etc.), and multiple rendering backends (rasterizer, raytracer, batch renderer). Robotics-specific features include URDF/MJCF/USD asset import, inverse kinematics, PD control, and reinforcement learning integration via rsl-rl. The codebase is well-structured with extensive tests, CI/CD pipelines, and a large set of examples covering manipulation, locomotion, deformables, fluids, and coupling scenarios. While the engine is primarily an application library, it also serves as a research platform for differentiable physics and novel simulation techniques.