Hi,

Yes, Odoo POS allows you to use the point of sale offline, and it is a useful feature when you don't have an internet connection. You can refer to this video.

https://www.youtube.com/watch?v=bbljz-AZGiw

Regards

There's a small missunderstanding. 
first of all, if you wanna launch a POS session you MUST have internet. Even if it's a smartphone shared connexion, for the launch you must be online.

POS app will launch on your internet's browser all datas in memory. 
After that. On the top right you'll se a green logo (looks like the wifi's pictogram).
When the POS app is online and if you have an active connexion. All operations will be immediatly synchronized the Odoo's backoffice.

When you don't have an active internet connexion, this logo will become red. 
You can still work and make transactions, but all those datas are stocked by the web browser. 

To resume : you can't launch POS offline, but when it's done, if you have a internet shutdown, you can still work...