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What is the Zephyr Project?

The Zephyr® Project is an open source scalable real-time operating system (RTOS) supporting multiple hardware architectures including ARC, ARM, RISC-V and X86. The Zephyr OS is a proven RTOS used in products today. 

Zephyr OS is modular and supports multiple architectures, developers can easily tailor an optimal solution to meet their needs. Zephyr OS is used in a broad spectrum of applications from simple connected sensors to complex edge systems. 

As an open source project, the community contributes to the evolution of Zephyr by adding support for new hardware, developer tools, sensors and device drivers. Enhancements in security, device management capabilities, connectivity stacks and file systems are easily implemented.

What is the vision for Zephyr?

Built with security and safety in mind, Zephyr’s vision is to be the best-in-class open source RTOS ecosystem for connected and resource-constrained devices by bringing together a diverse set of silicon vendors, development tool vendors, OEMs, ODMs, and ISVs.

What makes the Zephyr Project "open"?

The Zephyr Project operates as a community-based, open source RTOS that lives and breathes the “open source way”. The project welcomes open discussion and active participation from a broad range of organizations and market segments in order to be useful to the largest number of developers worldwide across industries.

The community is the cornerstone to the Zephyr open source project and will continue to contribute new ideas & functionality. Contact us now if you are interested in taking an active role.

What is the rationale for choosing the Apache 2.0 license?

The Zephyr Project chose Apache 2.0 for three main reasons:

  • It’s an Open Source Initiative (OSI)-approved, permissive license that is in broad use and well known.  
  • It has a well understood grant of patent rights by contributors to the code base.
  • It allows the community and customers to use the code and while we’d like them to contribute code back to the community, the license does not mandate this.  Compliance with the license just requires preservation of copyright and license notices. 

This choice of license has enabled the Zephyr Project to expand participation and membership to a broad set of organizations including those who have not typically participated in open source development in the past.  To learn more about the Apache 2.0 license see:,  and for those who would like to read a summary in plain english see:

What is the project's position on safety certification?

The Zephyr Project Governing Board is exploring various safety certifications and their relative values for members. Safety certifications require strict development processes best implemented with a parallel code base, which likely would require additional engineering resources beyond those devoted to the current project roadmap. If you’re interested in learning more about these conversations and wish to participate, we’d love to know what you think. Engage with the community on Discord, and become a member today.

To what extent is security integrated into the project and how ready is it for security audit?

The Security Working group is exploring a security audit and will make recommendations comprising readiness, breadth of implementation, and resources required to the Governing Board. To find out more about how you can participate, please contact:

What boards are supported by the Zephyr Project?

Zephyr Project supports over 500+ boards across multiple architectures including ARC*, ARM, Nios II, RISC-V, SPARC, Tensilica, and x86. Details regarding the full list of boards supported can be found here.

What is the Zephyr Release Process

The Zephyr Project releases on a time-based cycle, rather than a feature-driven one. Zephyr releases represent an aggregation of the work of many contributors, companies, and individuals from the community. Zephyr follows a roughly 4 month release cycle. For details please click here.

What is the LTS policy for the Zephyr project?

Long-term support releases are designed to be supported and maintained for an
extended period and is the recommended release for products and the auditable branch used for certification. See the full LTS policy at