  We prove the stability of global equilibrium in a multi-species mixture,
where the different species can have different masses, on the $3$-dimensional
torus. We establish stability estimates in $L^\infty_{x,v}(w)$ where $w=w(v)$
is either polynomial or exponential, with explicit threshold. Along the way we
extend recent estimates and stability results for the mono-species Boltzmann
operator not only to the multi-species case but also to more general hard
potential and Maxwellian kernels.
