Anyone using S3 API with ATMOS?

I'm looking for an easy windows-based utility to validate it has been set up correctly.

We are planning to use ATMOS storage (for the time being) to give our development team "internal S3 buckets".  I think we will create a subtenent when a group requests access, then send them the subtenant name, ID, UID, and Shared Secret.  Prior to releasing to our general public, I wanted to validate it is set up correctly and usable.  I work for a very secure company and am unable to just downlad and install internet utilities on my laptop.  I have to request the utility and it goes through a certification process.

So...I see there are a number of utilities available, but wondering what others may use.  I think I would like to use the AWS cli since it can be installed on Windows (as well as Linux and Mac), and could be useful for others in our company.  I read through the setup and belive it will work (although the region parm might cause a challange).

Is there anyone using this utility?  Any other suggestions?  Need Linux, MAC, and Windows.  ANd, would rpefer free ;-).

Thanks,

Mike