  The main irreducible background in the T2K $\nu_e$ appearance analysis is the
$\nu_e$ contamination in the $\nu_\mu$ beam. In order to quantify this
background, a selection for charged-current $\nu_e$ interactions in the near
detector (ND280) tracker region was developed by combining the particle
identification abilities of the time projection chambers and electromagnetic
calorimeters. We measured a data/MC ratio of $1.01 \pm 0.10$ for the $\nu_e$
component of the beam which, is an important confirmation of our predictions of
the expected backgrounds. In 2014 the T2K experiment reversed the polarity of
the magnetic horns and began running with an antineutrino beam for the first
time. Differences in the oscillation probabilities between neutrinos and
antineutrinos may provide insight into CP violation in the leptonic sector. The
current ND280 Tracker $\nu_e$ charged-current selection has been used as a
starting point for the $\bar{\nu_e}$ charged-current selection. The additional
challenges and selection criteria of the electron anti-neutrino selection will
be presented.
