  We introduce APPLE, a novel planetary evolution code designed specifically
for the study of giant exoplanet and Jovian planet evolution in the era of
Galileo, Juno, and Cassini. With APPLE, state-of-the-art equations of state for
hydrogen, helium, ice, and rock are integrated with advanced features to treat
ice/rock cores and metals in the gaseous envelope; models for helium rain and
hydrogen/helium immiscibility; detailed atmosphere boundary tables that also
provide self-consistent albedos and spectra; and options to address envelope
metal gradients and stably-stratified regions. Our hope is that these
purpose-built features of APPLE will help catalyze the development of the next
generation of giant exoplanet and Jovian planet evolutionary models.
