Hey Ralf, Thank you so much for your answer. scipy.cython_scipy sounds good to me, but TBH I care most about the fact that the functionality exists, so I might not be the best to juge. Else, how about scipy.cython_lib ? Or just scipy.cython since LowLevelCallable is exposed right at the root of scipy (that's quite unique afaik btw) My own code lives at https://github.com/gabrielfougeron/choreo/tree/main/choreo/scipy_plus/cython . I wrote it mimicking what I read in scipy.integrate.quad. The purpose of the code is to provide symplectic integrators for partitioned hamiltonian systems following this issue https://github.com/scipy/scipy/issues/12690 Would you rather continue this discussion here or on github ? (I'm asking in particular because I don't get notified here) Cheers, Gabriel