License Details
[About FreeRTOS]

Options

FreeRTOS is licensed under a modified GPL and can be used in commercial applications under this license. An alternative commercial license option is also available in cases that:

You cannot fulfill the requirements stated in the "Modified GPL license" column of the table below.
You wish to receive direct technical support.
You wish to have assistance with your development.
You require legal protection or other assurances.

License feature comparison

	FreeRTOS Modified GPL license	OpenRTOS Commercial license
Is it free?	Yes	No
Can I use it in a commercial application?	Yes	Yes
Is it royalty free?	Yes	Yes
Do I have to open source my application code that makes use of the FreeRTOS services?	No, as long as the code provides functionality that is distinct from that provided by FreeRTOS	No
Do I have to open source my changes to the kernel?	Yes	No
Do I have to document that my product uses FreeRTOS.org?	Yes a WEB link to the FreeRTOS.org site is sufficient	No
Do I have to offer to provide the FreeRTOS.org code to users of my application?	Yes	No
Can I receive professional technical support on a commercial basis?	No, FreeRTOS is supported by an online community	Yes
Is a warranty provided?	No	Yes
Is legal protection provided?	No	Yes, IP infringement protection is provided

Commercial Licensing

	OpenRTOS^TM is a commercially licensed version of FreeRTOS.org. The OpenRTOS license does not contain any references to the GPL.
	SAFERTOS^TM is a derivative version of FreeRTOS.org that has been analyzed, documented and tested to meet the stringent requirements of the IEC 61508 safety standard. Complete safety lifecycle documentation artifacts have been created and independently audited to verify IEC 61508 SIL 3 conformance.

The SafeRTOS FAQ provides information on the differences between FreeRTOS.org, OpenRTOS and SafeRTOS.

Modified GPL (Open Source) Licensing

The FreeRTOS source code is licensed by the GNU General Public License (GPL) with an exception. The full text of the GPL is available here. The text of the exception is available at the bottom of this file.

The exceptions permits the source code of applications that use FreeRTOS solely through the API published on this WEB site to remain closed source, thus permitting the use of FreeRTOS in commercial applications without necessitating that the whole application be open sourced. The exception can only be used if you wish to combine FreeRTOS with a proprietary product and you comply with the terms stated in the exception itself.

The FreeRTOS download also includes demo application source code, some of which is provided by third parties AND IS LICENSED SEPARATELY FROM FREERTOS.

For the avoidance of any doubt refer to the comment included at the top of each source and header file for license and copyright information.

This is a list of files for which Real Time Engineers Ltd. is not the copyright owner and are NOT COVERED BY THE GPL.

Various header files provided by silicon manufacturers and tool vendors that define processor specific memory addresses and utility macros. Permission has been granted by the various copyright holders for these files to be included in the FreeRTOS download. Users must ensure license conditions are adhered to for any use other than compilation of the FreeRTOS demo applications.
The uIP TCP/IP stack the copyright of which is held by Adam Dunkels. Users must ensure the open source license conditions stated at the top of each uIP source file is understood and adhered to.
The lwIP TCP/IP stack the copyright of which is held by the Swedish Institute of Computer Science. Users must ensure the open source license conditions stated at the top of each lwIP source file is understood and adhered to.
Various peripheral driver source files and binaries provided by silicon manufacturers and tool vendors. Permission has been granted by the various copyright holders for these files to be included in the FreeRTOS download. Users must ensure license conditions are adhered to for any use other than compilation of the FreeRTOS demo applications.
The files contained within FreeRTOS\Demo\WizNET_DEMO_TERN_186\tern_code, which are slightly modified versions of code provided by and copyright to Tern Inc.

Errors and omissions should be reported to Richard Barry, contact details for whom can be obtained from the Contact page.

GPL Exception

Any FreeRTOS source code, whether modified or in it's original release form, or whether in whole or in part, can only be distributed by you under the terms of the GNU General Public License plus this exception. An independent module is a module which is not derived from or based on FreeRTOS.

EXCEPTION TEXT:

Clause 1

Linking FreeRTOS statically or dynamically with other modules is making a combined work based on FreeRTOS. Thus, the terms and conditions of the GNU General Public License cover the whole combination.

As a special exception, the copyright holder of FreeRTOS gives you permission to link FreeRTOS with independent modules that communicate with FreeRTOS solely through the FreeRTOS API interface, regardless of the license terms of these independent modules, and to copy and distribute the resulting combined work under terms of your choice, provided that

Every copy of the combined work is accompanied by a written statement that details to the recipient the version of FreeRTOS used and an offer by yourself to provide the FreeRTOS source code (including any modifications you may have made) should the recipient request it.
The combined work is not itself an RTOS, scheduler, kernel or related product.
The independent modules add significant and primary functionality to FreeRTOS and do not merely extend the existing functionality already present in FreeRTOS.

Clause 2

FreeRTOS may not be used for any competitive or comparative purpose, including the publication of any form of run time or compile time metric, without the express permission of Real Time Engineers Ltd. (this is the norm within the industry and is intended to ensure information accuracy).