Gyselalib++ provides the mathematical building blocks to construct kinetic or gyrokinetic plasma simulation codes in C++, simulating a distribution function discretised phase space on fixed grid. It relies Discrete Domain Computation (DDC) library (Padioleau et al., 2025) statically type discretisation dimensions, thus preventing many common sources of errors. Via DDC, also leverages Kokkos framework (Trott 2022), ensuring performance portability across various CPU and GPU architectures. The variety tools including semi-Lagrangian advection operators, quadrature rules, solvers for elliptic hyperbolic partial differential equations (PDEs). majority operators are designed work non-orthonormal coordinate systems; those that don’t use static typing raise compiler errors their misuse.