MZIBiastabilix is a precision tool crafted for photonics professionals to evaluate and control bias drift in Mach–Zehnder Interferometers under thermal variations. Unlike generic calculators, it integrates physics-based modeling with real-time validation, delivering accurate insights into phase drift, extinction ratio degradation, and thermal stability thresholds. Its modern interface, gradient visuals, and error-handling alerts make complex optical stability analysis both accessible and efficient. By translating subtle material and temperature effects into clear, actionable outputs, MZIBiastabilix empowers engineers and researchers to design more reliable integrated photonic systems with confidence.