Zephyr

In 2016, Nordic Semiconductor made a strategic decision by joining the Zephyr Project. At the time, it was a forward-thinking move—shifting focus from our mature and popular nRF5 SDK to an emerging, yet promising, open-source RTOS. We knew we had to make a change to offer the best possible software to our customers.

Why Zephyr?

Nordic Semiconductor evaluated several alternatives, including FreeRTOS, Apache MyNewt, Mbed OS, and others, but we saw something unique in the Zephyr Project. Zephyr RTOS is a real-time operating system designed specifically for secure, low-power, connected embedded devices. It scales seamlessly—from compact configurations suitable for simple, resource-limited devices to more complex, feature-rich configurations for high-performance, advanced devices.

What sets Zephyr apart is its comprehensive scope and strong foundation, which align well with Nordic's rich portfolio. Maintained by the Zephyr Project and hosted by the Linux Foundation, Zephyr is open source and governed in a vendor-neutral way, which fosters broad collaboration and rapid innovation. Beyond its modern kernel, Zephyr includes a rich ecosystem: middleware, cryptography and security features, file systems, a secure bootloader, shell, tracing and logging capabilities, and out-of-the-box support for 200+ sensor drivers and growing.

Key advantages included:

• A rich ecosystem, and not just a kernel 
• A scalable solution suitable for both the smallest constrained devices and the most advanced in Nordic's portfolio
• A vendor-neutral governance model that promotes collaboration
• A strong open source foundation, enabling reusable software, faster innovation, and quicker bug discovery and fixes
• A focus on security, maintainability, and modern development tools
  
  

Nordic saw an opportunity to build a Zephyr-based SDK leveraging these strengths, enhance it further, and deliver the best possible software offering to our customers. This became the nRF Connect SDK.

Nordic Semiconductor went All-In on the Zephyr Project

Nordic didn’t just contribute code. We made a strategic decision to go all-in on the Zephyr Project and invest:

• Early platinum membership in the Zephyr Project signaled our long-term commitment
• Took an active role on the governing board, even chairing it for a few years
• Chaired multiple working groups
• Contributed extensively to both the technical and marketing committees
• Dedicated significant engineering resources to upstream development
• Launched the Nordic Developer Academy, enabling thousands of developers to learn Zephyr and the nRF Connect SDK
  
  

Some of Nordic's key contributions to the Zephyr Project include:

• Bluetooth LE Controller
• DFU framework
• Complete USB stack
• OpenThread integration
• Support for CoAP, LwM2M, and MQTT
• Integration of Trusted Firmware-M (TF-M)
• Transition from Make to CMake
• Devicetree infrastructure
• West and the Zephyr module system (including support for binary blobs)
• Device framework and power management improvements
• Overhauled hardware (board and SoC) model
• Sysbuild (multi-build system for Zephyr)
• Logging and Shell subsystems
• …and many more
  
  

Industry standard

Today, the Zephyr Project has grown beyond what was initially envisioned. It has developed into a robust and dynamic technology ecosystem, with a steadily increasing number of members—several of whom are Nordic partners. Zephyr RTOS is now the most widely adopted RTOS in the embedded industry and is recognized as the de facto industry standard.

Nordic remains fully committed to the continued success of the Zephyr Project. We’re not just along for the ride; Nordic will continue to invest in, contribute to, and actively advance the Zephyr project. The goal is to ensure developers have the best possible development experience when building innovative IoT solutions.

nRF Connect SDK, Nordic Semiconductor’s main Software Development Kit, is based on the Zephyr RTOS. It integrates the RTOS and a wide range of full-fledged applications (Ex: nRF Desktop , Asset Tracker Template), samples, application and networking protocols, libraries, hardware drivers, and more. The nRF Connect SDK is a production-ready software development kit used in hundreds of products across various market verticals, including consumer, industrial, and medical.

Nordic Semiconductor chose to base its SDK on the Zephyr RTOS due to its rich ecosystem, its high configurability, and modularity. These offer developers the flexibility to build size-optimized software for memory-constrained devices as well as powerful and complex software for more advanced devices and applications. 

In addition to Zephyr’s rich ecosystem, nRF Connect SDK adds more libraries, networking protocols, and functionalities that are not part of Zephyr. To name a few: multiprotocol support (MPSL), 2.4 GHz proprietary, CryptoCell libraries, nRF91 Series modem libraries, and many more. It also includes all our prototyping platforms (Ex: Nordic Thingy:91 X) and reference designs (Ex: nRF Desktop).  

As part of the nRF Connect umbrella, we also offer many tools that aim to improve developers’ productivity and reduce time to market, such as the power profiler and various other tools as part of the nRF Connect for Desktop, and developer environments such as nRF Connect for VS Code. We also aim to equip developers with the technical information and the know-how to build tomorrow’s cutting-edge wireless products through our comprehensive Nordic Developer Academy online courses and documentation.