Micrium OS
Micrium OS: A free, modular RTOS stack for Silicon Labs EFR32 and EFM32 embedded projects. Ranked #4 of 14 in IoT Operating Systems by our editors (8.8/10); pricing: Free plan; best for silicon Labs devices needing a broad RTOS stack.
At a glance
- Editor score8.8 / 10
- PricingFree plan
- Best forSilicon Labs devices needing a broad RTOS stack
- Free planYes
- Paid fromFree
- Deployment modelEdge
- Facts checked24 Sep 2026
Where it wins
- Priority-based real-time multitasking with queues, semaphores, and event flags
- FAT file system plus USB host and device class support
- IPv4/IPv6 networking and CMSIS-RTOS2 Bluetooth adaptation
Where it doesn't
- Verified device support centers on Silicon Labs EFR32 and EFM32 families
- Self-hosted embedded RTOS, not a centralized fleet-management service
- Project support is provided through community resources and documentation
Our verdict on Micrium OS
Micrium OS is a modular real-time operating system for embedded applications built around a priority-based preemptive kernel. It is intended for developers working with Silicon Labs EFR32 and EFM32 devices who need to combine multitasking with connectivity and storage components. The system is available at no licensing cost for projects targeting those device families. Developers can select the kernel and add components such as file systems, USB stacks, and networking rather than adopting a cloud device-management service. Simplicity Studio distributes Micrium OS with project tools and examples, and the tooling is available for Windows, macOS, and Linux.
Its component breadth is the main reason to consider it. The kernel provides semaphores, task semaphores, event flags, queues, and task queues for coordinating embedded workloads. The file-system stack includes FAT support and storage-device drivers. USB coverage spans device classes including CDC, HID, and MSC, while the host stack supports MSC, HID, CDC, USB2Ser, and AOAP. TCP/IP networking includes IPv4 and IPv6, and a CMSIS-RTOS2 adaptation supports Bluetooth applications. Integration with Simplicity Studio and the Silicon Labs Bluetooth stack gives projects a defined vendor ecosystem, with documented support for Bluetooth, Connect, Wi-SUN, and Zigbee stack scenarios.
Micrium OS fits teams that want a broad, modular RTOS foundation while staying within Silicon Labs' embedded hardware families. Its self-hosted deployment keeps the focus on firmware and device-level capabilities, so teams seeking centralized fleet operations, subscription management, or OTA controls should evaluate a separate platform. The product is also not open source, and support channels are centered on community resources and documentation. Choose it when real-time scheduling, USB, storage, and IP networking belong in the device software; look elsewhere when the primary requirement is cloud orchestration across heterogeneous hardware.
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Micrium OS pricing
Micrium OS fact sheet
| Free plan | Yes |
|---|---|
| Paid from | Free |
| Deployment model | Edge |
| Supported device OS | Micrium OS; runs on Silicon Labs EFR32 and EFM32 devices |
| Over-the-air updates | Not verified |
| Fleet provisioning | Not verified |
| Protocol support | TCP/IP, IPv4, IPv6, USB, CAN; Bluetooth, Connect, Wi-SUN, Zigbee stack support |
| Certificate management | Not verified |
| Device limit | Not verified |
| Deployment | Self-hosted |
| Platforms | Windows, macOS, Linux |
| Support | Community, Docs |
| Built for | Small business, Mid-market, Enterprise (editorial estimate) |
| Integrations | 2 integrations: Simplicity Studio, Silicon Labs Bluetooth stack |
| Pricing | Free plan |
| Website | silabs.com |
| Facts checked | 24 Sep 2026 |
Micrium OS integrations
Micrium OS lists 2 integrations on its own site.
- Simplicity Studio
- Silicon Labs Bluetooth stack
Alternatives to Micrium OS
- VxWorksA broad, deterministic RTOS for teams building safety-critical embedded products.9.3
- QNX Neutrino RTOSA mature commercial RTOS for mission-critical embedded products and multicore targets.9.1
- Apache NuttXA free, configurable RTOS with broad documented hardware support and POSIX-oriented APIs.9.0
See all Micrium OS alternatives →
Micrium OS vs the competition
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- Micrium OS vs OpenWrt
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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
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