At the start of my career I mostly worked for Philips, in a team that specialised in (among other technologies) Bluetooth communication between a device and mobile phones.
Aiming to support as many Bluetooth-enabed devices as possible, we were testing with many different devices.
These devices were mostly blood pressure meters, weight scales and thermometers that expose their measurements digitally via Bluetooth.

Obtaining all the devices we want to support is quite a challenge, especially during the Corona-pandemic.
For that reason, and to save a bit on expenses, I developed SimDeviceBLE.
With SimDeviceBLE, it is possible to simulate a Bluetooth device.
Developers that want to test Bluetooth devices can assemble these from the available Services and Characteristics.

The app is developed with extensibility in mind.
Bluetooth is known for having many Services. Frequently a new service is added to the standard.
Because it is an open source project, anyone can add their desired Bluetooth Services.