  Cold Dark Matter particles may interact with ordinary particles through a
dark photon, which acquires a mass thanks to a spontaneous symmetry breaking
mechanism. We discuss a dark photon model in which the scalar singlet
associated to the spontaneous symmetry breaking has an effective potential that
induces a first order phase transition in the early Universe. Such a scenario
provides a rich phenomenology for electron-positron colliders and gravitational
waves interferometers, and may be tested in several different channels. The
hidden first order phase transition implies the emission of gravitational waves
signals, which may constrain the dark photon's space of parameters. Compared
limits from electron-positron colliders, astrophysics, cosmology and future
gravitational waves interferometers such as eLISA, U-DECIGO and BBO are
discussed. This highly motivates a {\it cross-checking strategy} of data
arising from experiments dedicated to gravitational waves, meson factories, the
International Linear Collider (ILC), the Circular Electron Positron Collider
(CEPC) and other underground direct detection experiments of cold dark matter
candidates.
