There is an immediate need to develop Grid interfaces for a large set of numerical software libraries, in order to make popular software of today available in the computing infrastructure of tomorrow. As this development work tend to be both tedious and error-prone, this contribution presents a semi-automatic process for generating the interfaces. The underlying principle is to use a front-end tuned for each numerical library and a back-end for each Grid environment considered. Then all library—Grid environment combinations can be generated with a small amount of manual work. The presentation of the main ideas is followed by a proof-of-concept implementation that generates NetSolve interfaces for the complete SLICOT software library, a numerical library comprising nearly 400 Fortran subroutines for numerical computations in the design and analysis of control systems.