# Licencing question

**URL:** <https://forums.freertos.org/t/licencing-question/4812>\
**Category:** Kernel\
**Created:** [December 9, 2010, 10:42am UTC](https://forums.freertos.org/t/licencing-question/4812 "2010-12-09T10:42:06Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![system](https://d2v6vdsk2p900z.cloudfront.net/original/1X/7fc8fdb729c645aab5b20282bbe34e57cb407be6.jpeg) [@system](https://forums.freertos.org/u/system)\
**Post date:** [December 9, 2010, 10:42am UTC](https://forums.freertos.org/t/licencing-question/4812/1 "2010-12-09T10:42:06Z")

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**[riccardomanfrin](https://sourceforge.net/u/riccardomanfrin/)** wrote on [Thursday, December 09, 2010](https://sourceforge.net/p/freertos/discussion/382005/thread/d2087208/#6fac):

Reading the exceptions to the FreeRTOS GPL licence provided in [this](http://www.freertos.org/index.html?http://www.freertos.org/a00114.html#exception) page, I’d like to be clarified regarding the permissions to use FreeRTOS on a commercial software project.  
More specifically, assume I develop an **independent** module that stays **on top of** FreeRTOS and relays on it. As I’m not satisfied with the off-the-shelf provided FreeRTOS APIs, I make modifications to FreeRTOS and maybe extend its set of APIs.  
If I release those modifications and APIs under your modified GPL licence, can I still close the module with a commercial licence?  
Thanks in advance.  
RM

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**Author:** ![rtel](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/rtel/32/31_2.png) [@rtel](https://forums.freertos.org/u/rtel)\
**Post date:** [December 9, 2010, 10:50am UTC](https://forums.freertos.org/t/licencing-question/4812/2 "2010-12-09T10:50:37Z")

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**[rtel](https://sourceforge.net/u/rtel/)** wrote on [Thursday, December 09, 2010](https://sourceforge.net/p/freertos/discussion/382005/thread/d2087208/#20f4):

In very simple terms the API is the boundary between what must be open sourced and what need not be.&nbsp; If you extend or change the API then the new API and any changes to the code necessary to use the API will have to be open source.&nbsp; Your code that calls your API need not be.

Regards.