  We present the new version of OpenLoops, an automated generator of tree and
one-loop scattering amplitudes based on the open-loop recursion. One main
novelty of OpenLoops 2 is the extension of the original algorithm from NLO QCD
to the full Standard Model, including electroweak (EW) corrections from gauge,
Higgs and Yukawa interactions. In this context, among several new features, we
discuss the systematic bookkeeping of QCD-EW interferences, a flexible
implementation of the complex-mass scheme for processes with on-shell and
off-shell unstable particles, a special treatment of on-shell and off-shell
external photons, and efficient scale variations. The other main novelty is the
implementation of the recently proposed on-the-fly reduction algorithm, which
supersedes the usage of external reduction libraries for the calculation of
tree-loop interferences. This new algorithm is equipped with an automated
system that avoids Gram-determinant instabilities through analytic methods in
combination with a new hybrid-precision approach based on a highly targeted
usage of quadruple precision with minimal CPU overhead. The resulting
significant speed and stability improvements are especially relevant for
challenging NLO multi-leg calculations and for NNLO applications.
