Julia has historically been built against a single backing BLAS/LAPACK library, and switching to a different library has required a recompilation of Julia. This was compounded by issues with loading 3rd party binaries that linked against incompatible BLAS backends. This talk will showcase a new low-overhead compatibility layer in Julia v1.7 named libblastrampoline that allows for runtime switching of BLAS/LAPACK libraries, as well as allowing loading of multiple BLAS/LAPACK ABIs at once.