Particle Electron - third party SIM & Cloud

Hello,

I am new to the Particle area, and I plan to use the particle electron for my iot project.

My question is: can I use the particle Electron “hardware only”, meaning with our custom backend (so without particle cloud subscription)?
We would use a third party sim card as well.

Thank you for your help

Yes you can - but you sacrifice some good stuff and may have to jump through extra hoops to achieve some of the features otherwise provided for free (e.g. encrypted communication).