  Coalescing neutron star--white dwarf (NS-WD) binaries are among the primary
targets for upcoming space-borne gravitational wave (GW) detectors such as
LISA, TaiJi, TianQin, etc. During close interaction, these binaries undergo
mass transfer, emitting simultaneous X-rays and GWs. This offers a unique
opportunity to measure mass transfer rates and study compact binary evolution.
To analyze mass transfer rates, we employ the TaylorF2 frequency domain
waveform model within the stationary phase approximation (SPA). Through this
approach, we derive the GW phase induced during the mass transfer phase and
perform Markov Chain Monte Carlo (MCMC) simulations to estimate the minimal
detectable mass transfer rate given specific signal-to-noise ratios (SNRs). Our
results suggest that for a NS-WD binary with a $0.5 \rm M_\odot$ white dwarf
companion, we could measure mass transfer rates down to $10^{-7}\rm M_\odot ,
{\rm yr}^{-1}$ at SNR=20 and $10^{-9}\rm M_\odot , {\rm yr}^{-1}$ at SNR=1000.
This measurement holds significance for studying compact binary evolution
involving mass transfer and has potential applications in forecasting tidal
disruption events.
