Are there any smart light switches/dimmers that support Bluetooth Low Energy and have an open or accessible APIs?
I want to gradually replace all dumb switches in my house with smart switches, but don't want to deal with any proprietary apps. Are there any such switches?
In general Bluetooth equipment always comes with a proprietary app for your phone...
I think that if you want to have the control over your Bluetooth switches, you might want to take a look at Arduino Bluetooth modules and command relays on it to toggle normal lamps.
The closest to an answer that I can come to is this list of products supported by openhab. It doesn't identify which products use Bluetooth LE, but does identify products (indirectly) where the protocol is known.