The Twilio Microvisor is a new IoT Device Builder Platform that leverages the Arm TrustZone technology for Cortex-M processors to offer unmatched IoT security and powerful features such as remote debugging and fail-safe over-the-air updates. The platform will first target the low-power STM32U5 family from STMicroelectronics, which offers enhanced performance and cybersecurity features including hardware-resistant AES encryption and secure data storage. Microvisor enables secure partitioning of application code and runtime environments, and integrates with existing OS, development environment, and toolchain. It also provides a "hypervisor for microcontrollers" approach that adapts to various embedded development approaches, allowing device builders to selectively add in secure IoT foundation components through simple APIs. The first supported MCU is the STM32U585, which enables the Microvisor approach with its enhanced cybersecurity features such as Active tamper detection and internal monitoring. The platform will be accessible through a public beta release expected by mid 2022, and pricing will remain transparent and easy to understand.