Using Bluetooth on a desktop computer is now such a seamless process; it’s something built-in and just works. Behind that ubiquity is a protocol layer called HCI, or Host Controller Interface… ...

You can potentially get a two-for-one deal here because the application can also be used to program boards, though it’s primarily optimized for ESP32 and ESP8266 variants.

The latest development in the ESP32 world comes from [femtoduino] who, as the name suggests, makes very small things. This one is a complete ESP32 which fits inside a USB-A connector.