List of the Top 12 Real-Time Operating Systems (RTOS) for Linux in 2025

Created through a partnership with leading chip manufacturers over a period of 15 years, FreeRTOS is currently downloaded roughly every 170 seconds and is recognized as a premier real-time operating system (RTOS) designed specifically for microcontrollers and small microprocessors. It is freely accessible under the MIT open source license and features a core kernel along with a growing suite of IoT libraries that serve various sectors. Emphasizing reliability and ease of use, FreeRTOS has garnered a reputation for its robust performance, lightweight design, and broad compatibility with numerous devices, making it the preferred choice for microcontroller and small microprocessor solutions among major global companies. Users benefit from a variety of pre-configured demos and IoT reference integrations, which facilitate straightforward project setups, thus allowing for rapid downloading, compiling, and quicker market entry. This efficient approach not only streamlines development but also supports faster innovation cycles. Additionally, the ecosystem of partners provides a wide array of options, bridging community-driven initiatives with professional support, ensuring users have the vital resources necessary for their success. As the landscape of technology evolves, FreeRTOS is dedicated to continually adapting and enhancing its features to address the shifting needs of the industry, proving its resilience and relevance in a dynamic environment. Moreover, its ongoing commitment to innovation positions it as a key player in the future of real-time operating systems.

Arm Mbed OS is a freely available operating system specifically designed for Internet of Things (IoT) applications, equipping developers with the essential resources to create advanced IoT devices. This powerful operating system is optimized for smart and connected products that utilize Arm Cortex-M architecture, providing features like machine learning capabilities, secure connectivity options, an RTOS kernel, and drivers for a range of sensors and I/O devices. Tailored for the needs of the Internet of Things, Arm Mbed OS encompasses functionalities in connectivity, machine learning, networking, and security, along with an extensive library of software, development boards, tutorials, and real-world examples. It encourages collaboration within a broad ecosystem, supporting over 70 partners across various sectors, including silicon manufacturers, module developers, cloud service providers, and OEMs, thus broadening the options available for developers. By utilizing the Mbed OS API, developers can produce clean, portable, and easy-to-manage application code while also taking advantage of enhanced security, communication, and machine learning features. This integrated solution not only simplifies the development process but also significantly reduces costs, shortens development time, and mitigates risks. Moreover, Mbed OS facilitates innovation by allowing developers to quickly prototype and confidently deploy IoT solutions, ultimately driving technological advancement in the field. The comprehensive support provided by the Mbed community further enriches the development experience, making it an ideal choice for both novice and experienced developers alike.

The SCIOPTA architecture is expertly designed to deliver exceptional real-time performance while keeping its dimensions compact. Its internal data structures, memory management strategies, interprocess communication mechanisms, and time management features are all optimized for peak efficiency. Operating as a pre-emptive real-time kernel, SCIOPTA is capable of handling interrupts at any time, even while the kernel is actively executing tasks. This operating system employs a message-based framework, offering a comprehensive set of system calls that enhance effective resource allocation and management. By utilizing standardized processes and interprocess communication protocols, SCIOPTA fosters system designs that are not only straightforward to implement but also easy to maintain over time. The robust messaging system facilitates seamless communication between processes and allows for the organization of processes into coherent modules, making SCIOPTA particularly beneficial for collaborative projects of considerable scale. Additionally, the streamlined architecture significantly shortens time-to-market, thereby improving overall project efficiency. Furthermore, the direct message passing feature not only supports interprocess communication but also aids in synchronization, which further refines system performance, making SCIOPTA a valuable asset in any development environment. Its ability to handle complex project needs with ease underscores its versatility and effectiveness.

Since its launch in 1980, QNX has become the preferred option for numerous businesses aiming to adopt real-time operating systems that provide an ideal mix of performance, security, and reliability for their critical operations. At the heart of QNX's advancements is the QNX Neutrino® Real-time Operating System (RTOS), a robust platform that supports the creation of cutting-edge products across diverse industries where reliability is crucial, including automotive, healthcare devices, robotics, transportation, and industrial embedded systems. QNX's microkernel architecture plays a vital role in maintaining system integrity by ensuring that a failure in a single component does not affect the function of others or compromise the kernel; any faulty part can be halted and restarted without disrupting the overall system. The QNX Neutrino RTOS distinguishes itself by delivering the determinism characteristic of real-time operating systems, utilizing strategies such as adaptive partitioning to guarantee that critical processes receive the necessary processing time to complete their tasks on schedule, while also meeting the performance demands of complex embedded systems. This array of features positions QNX Neutrino RTOS as a top choice for developers aiming to build strong and dependable applications. Furthermore, as technological advancements continue to unfold, the flexibility inherent in QNX's solutions guarantees that they stay ahead in the realm of real-time operating systems. Consequently, businesses can confidently rely on QNX to meet their evolving operational needs with cutting-edge technology.

Deos™, created by DDC-I, is a real-time operating system (RTOS) focused on safety and rigorously verified in alignment with DO-178C/ED-12C Design Assurance Level A (DAL A) standards for avionics use. This RTOS is compatible with ARINC 653 APEX and employs rate monotonic scheduling (RMS), specifically engineered to fulfill the FACE Safety Base Profile requirements. Since receiving its initial verification from Transport Canada in 1998, Deos has established itself as a reliable solution within the aviation sector, earning certification that permits its operation in countless aircraft. Over the last twenty years, it has continually adapted, integrating new processors and features to showcase its versatility and robustness. Additionally, Deos has successfully passed audits from numerous global certification bodies such as the FAA, ENAC, JAA, EASA, and CAAC, along with assessments by designated engineering representatives from various avionics and airframe manufacturers, guaranteeing that it remains in compliance with the highest industry standards. This ongoing commitment to development and verification not only reinforces its reliability but also positions Deos as an essential element in the landscape of modern aviation safety systems. Furthermore, its ability to evolve alongside technological advancements ensures that it remains at the forefront of safety-critical software solutions.

INTEGRITY utilizes robust hardware memory protection to effectively separate and protect embedded applications. By employing secure partitions, it guarantees that each task can access the necessary resources for optimal performance while concurrently safeguarding both the operating system and user tasks against malicious and erroneous code, including threats such as denial-of-service attacks, worms, and Trojan horses. To assist developers in accelerating their product development, Green Hills Software offers an extensive suite of middleware that has been thoroughly integrated and validated for compatibility with INTEGRITY, which features file systems like FFS, FAT, NFS, and journaling, alongside IPv4 and IPv6 networking stacks and a FIPS 140-2 certified Suite B embedded encryption library, among many other essential tools. Each middleware package has successfully passed rigorous pre-integration testing to ensure seamless functionality with the advanced features of INTEGRITY's real-time operating system. Additionally, Green Hills Software provides specialized platforms tailored for different industries, creating a fully integrated ecosystem that includes the INTEGRITY RTOS along with critical development tools, all aimed at further simplifying the development process. This comprehensive strategy not only enhances operational efficiency but also significantly fortifies the security of embedded applications, ensuring they can withstand various cybersecurity threats effectively.

The MQX real-time operating system (RTOS) offers outstanding real-time performance while ensuring a small and adaptable footprint. This operating system is perfectly integrated with NXP's 32-bit MCUs and MPUs and includes vital device drivers that are frequently used in embedded systems. With its modern, component-based microkernel design, the MQX RTOS enables developers to customize features, dimensions, and efficiency by selectively incorporating components, thus meeting the rigorous memory constraints common in embedded environments. Impressively, it can operate with as little as 8 KB of ROM and 2.5 KB of RAM on the Arm Cortex M4, which accommodates the kernel, two task applications, a lightweight semaphore, the interrupt stack, queues, and the memory manager. This setup guarantees that a complete RTOS core is present while still providing optional services as required. By connecting components only when necessary, the system effectively prevents needless memory waste from functions that are not utilized. Additionally, essential components are available in both standard and lightweight variations, which enhances flexibility in terms of size, memory consumption, and performance options, making it an excellent choice for a wide range of applications. Furthermore, the adaptability of the MQX RTOS makes it suitable for projects with varying demands and constraints, allowing engineers to optimize their designs for specific needs.

OpenWrt is a flexible GNU/Linux distribution crafted specifically for embedded devices, with a particular focus on wireless routers. Unlike many other router firmware options, OpenWrt is built from scratch to deliver a fully customizable operating system tailored for embedded environments. This approach guarantees that users can utilize all critical functionalities without the burden of excess features, as it operates on a contemporary Linux kernel. Instead of providing a static firmware solution, OpenWrt offers a completely writable filesystem along with optional package management capabilities. This adaptability frees users from constraints set by manufacturers concerning application selections and settings, thereby enabling personalized adjustments to satisfy unique application requirements. Additionally, for developers, OpenWrt presents a powerful platform that allows for the development of applications without the need to construct an entire firmware image or distribution around them, which streamlines the development workflow. Consequently, OpenWrt stands out as an attractive option for both end-users who desire customization and developers looking for ease of use. Its commitment to flexibility and user control makes it a compelling choice in the realm of embedded operating systems.

Enea OSE stands out as a robust and effective real-time operating system meticulously crafted for multi-processor setups that require true deterministic real-time performance along with remarkable reliability. By optimizing the development workflow, it enhances system dependability and reduces long-term maintenance costs across a wide range of sectors, such as wireless communications, automotive technologies, medical apparatus, and telecom networks. Specifically designed for systems that prioritize communication and control, Enea OSE is adept at achieving high performance while adhering to strict real-time constraints. Its extensive adoption across various fields, including telecommunications, industrial automation, and embedded systems, highlights its importance in contemporary technological landscapes. The Enea OSE multicore kernel, a recipient of two esteemed accolades, merges the intuitive benefits of Symmetric Multi-Processing (SMP) with the scalability and precise performance of Asymmetric Multi-Processing (AMP), all while ensuring the high efficiency typical of bare metal operations. This distinctive design not only positions Enea OSE as an attractive option for developers but also fosters innovation in multi-core application development. As such, it continues to lead the way in providing solutions that prioritize both performance and reliability in an ever-evolving technological environment.

PikeOS is an advanced hypervisor built on a separation kernel, designed to enable numerous partitions for various operating systems and applications. This platform facilitates the development of intelligent devices tailored for the Internet of Things. Renowned for its robust protection against cyber-security threats, PikeOS is an ideal solution for systems needing stringent security measures, thanks to its innovative separation kernel design. It enjoys widespread adoption, being utilized in millions of edge and IoT devices, and has also found applications in essential communications infrastructure. PikeOS merges virtualization and real-time capabilities through pioneering technologies that are unparalleled in the industry. Additionally, it allows for the integration of multiple intricate embedded circuit boards onto a single hardware platform. Furthermore, PikeOS demonstrates versatility by accommodating new hardware architectures, such as Big-SoCs, which incorporate various heterogeneous cores. This hypervisor is compatible with multiple architectures and can support processors equipped with a memory management unit (MMU). With its unique capabilities, PikeOS stands out as a leading solution in the realm of secure and efficient computing.

This system encompasses a wide array of devices, from fundamental embedded environmental sensors and LED wearables to sophisticated embedded controllers, smartwatches, and IoT wireless applications, featuring a configurable architecture that includes stack-overflow protection, permission tracking for kernel objects and device drivers, and enhanced thread isolation through thread-level memory protection across various architectures such as x86, ARC, and ARM, along with distinct userspace and memory domains. Additionally, for systems that do not have a Memory Management Unit (MMU) or Memory Protection Unit (MPU) and those constrained by limited memory, it facilitates the combination of application-specific code with a customized kernel to create a monolithic image that can be seamlessly loaded and executed on the hardware. Within this framework, both the application and kernel code function within a single address space, promoting efficient resource management and performance enhancements. Consequently, this architecture is adept at enabling even the most resource-limited environments to effectively utilize advanced applications and sophisticated functionalities, thereby broadening the scope of what can be achieved in embedded systems.

Wind River's eLxr Pro represents a powerful, enterprise-level Linux platform designed for an extensive array of applications that span from the cloud to edge computing, adept at managing essential tasks including artificial intelligence, machine learning, and computer vision. Built upon the open-source eLxr framework, this solution not only provides flexible, long-term support but also includes ongoing security updates and monitoring. It ensures seamless compatibility with a spectrum of hardware accelerators while adhering to vital industry compliance requirements. Furthermore, eLxr Pro boosts organizational efficiency through tailored consulting services and optimizations, empowering businesses to scale their edge computing operations effectively while managing costs, maintaining security, and maximizing resource efficiency. By integrating these advanced features, eLxr Pro equips enterprises with the tools necessary to succeed in a rapidly evolving digital environment, fostering innovation and operational excellence. Ultimately, its comprehensive support allows organizations to focus on their core objectives while leveraging technology to drive growth.