As pet care systems evolve from simple identification tags into sophisticated IoT-enabled networks, current near-field communication (NFC) microchip-based pet care systems face challenges related to interoperability, limited sensing capabilities, and fragmented data management. Therefore, for improving the pet care system, the technical requirements and functional design criteria were examined for a sensor-integrated, NFC-enabled IoT pet microchip application in this study. Using the fuzzy analytic hierarchy process, 32 experts from veterinary medicine, IoT engineering, and user experience design evaluated a three-level hierarchy comprising 6 criteria and 24 subcriteria. The results reveal that health management is the most significant dimension [a weight (w) of 0.1724], followed by identification and registration (w = 0.1690), underscoring a shift from basic tracking to active medical monitoring. At the subcriteria level, controlled medical information sharing showed the highest global weight (w = 0.0465), highlighting the need for owner-authorized secure data exchange. Other important factors include NFC scanning reliability (w = 0.0455), data accuracy and traceability (w = 0.0455), and smartphone operating system/device compatibility (w = 0.0452). The results provide a reference for sensor technology development and propose the integration of biometric sensing, high-stability antenna arrays, and hardware-based encryption modules. An actionable roadmap can be established for developing integrated, trust-centered ecosystems for sustainable smart pet care.