Zephyr RTOS is a popular open-source real-time operating system used in embedded systems. It is known for its low-power consumption, small footprint, and support for various connectivity protocols. What many developers may not know is that Zephyr RTOS has had POSIX support since version 1.9, released back in 2017. This feature enables portability of software between different platforms and operating systems, allowing developers to run software written for other systems on top of the Zephyr RTOS with minimal efforts. In this presentation, we will showcase the advantages of using POSIX support in Zephyr, including reduced development time and cost, and increased compatibility with existing software. We will provide an overview of Zephyr's POSIX implementation, highlighting the supported APIs and limitations. Real-world use cases will be presented to demonstrate how POSIX support in Zephyr can unlock new possibilities in embedded systems development. We will also discuss the challenges and considerations when implementing and/or using POSIX in Zephyr RTOS.