The FreeRTOS Project

Twenty three official architecture ports - more than 6000 downloads per month.

* Immediate Free Download * Feature Rich * Easy To Use Pre-configured Projects * Can Be Used in Commercial Applications * Large User Community * Free Forum Support * Optional Commercial Licensing * Optional Commercial Support * Safety Critical Version Available * Expert Development Services * One RTOS for 23 Architectures * Smallest Footprint


FreeRTOSTM is a portable, open source, royalty free, mini Real Time Kernel - a free to download and free to deploy RTOS that can be used in commercial applications without any requirement to expose your proprietary source code. Downloaded more than 77,500 times during 2008, FreeRTOS is the cross platform de facto standard for embedded microcontrollers.

Each official port includes a pre-configured example application demonstrating the kernel features, expediting learning, and permitting 'out of the box' development. Support is provided by an active user community.


OpenRTOSTM is a commercially licensed and supported version of FreeRTOS that includes fully featured professional grade USB, file system and TCP/IP components.


SafeRTOSTM is a SIL3 RTOS version that has been certified for use in safety critical applications. It is a functionally similar product for which complete IEC 61508 compliant development/safety lifecycle documentation is available (conformance certified by TÜV SÜD, including compiler verification evidence).


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"The new book is great, it provides very helpful easy to understand examples of FreeRTOS concepts. The book is also an easy read free of unexplained arcane language and concepts... Excellent!!!" - Darrell F.



"It's probably safe to say at this point that FreeRTOS goes through more 'peer-review' than any other RTOS available on the planet. I have used it in several projects - one of which was a multiprocessor environment that used more than 64 processors and needed to run for months reliably. The FreeRTOS core performed well. Take FreeRTOS for a spin." - John Westmoreland

Why choose FreeRTOS?

Here are some reasons why FreeRTOS is a good choice for your next application - FreeRTOS...

Existing ports:



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Any and all data, files, source code, html content and documentation included in the FreeRTOSTM distribution or available on this site are the exclusive property of Real Time Engineers Ltd.. See the files license.txt (included in the distribution) and this copyright notice for more information. FreeRTOSTM and FreeRTOS.orgTM are trade marks of Real Time Engineers Ltd..