I have Yeelight Blubs White and Color.
I would like to know if there is a way (with developper access ? ) to use Yeelight Blubs without being connected to Cloud Servers ?
You can download some 3rd party Apps, they are using local control mode. We are planning to support local mode in official Yeelight app in next release.
Weiwei can the local mode be used for a smart app for smart things?
No, SmartThings uses a very heavy local control mode which we can't support in firmware.
Home Assistant can control the lights locally, there's also OpenHAB and some other