  We present t$|$ket$\rangle$, a quantum software development platform produced
by Cambridge Quantum Computing Ltd. The heart of t$|$ket$\rangle$ is a
language-agnostic optimising compiler designed to generate code for a variety
of NISQ devices, which has several features designed to minimise the influence
of device error. The compiler has been extensively benchmarked and outperforms
most competitors in terms of circuit optimisation and qubit routing.
