how to turn off session

[eluser]scieck[/eluser]
thanks,
I inherited a project running on CI, I built a REST API on top of it, I don't have full knowledge of the code base yet. I can see from the HTTP headers that session cookies are passed in the responses and as I am not "loading it (session)" in the REST section I wrote it means the session is initiated somewhere else.
I'll look for it, thanks again.