  We introduce the shifted quantum affine algebras. They map homomorphically
into the quantized $K$-theoretic Coulomb branches of $3d\ {\mathcal N}=4$ SUSY
quiver gauge theories. In type $A$, they are endowed with a coproduct, and they
act on the equivariant $K$-theory of parabolic Laumon spaces. In type $A_1$,
they are closely related to the open relativistic quantum Toda lattice of type
$A$.
