This Bluetooth Test Tool is an easy tool to use for developing software and hardware using Bluetooth Low Energy peripherals.
One can easily set the UUID of the BLE device, the UUIDs of the RX and TX peripheral services and (optionally) auto connect to the device. If the peripheral successfully connects, a textfield shows and you can now send messages from the iOS device to the BLE devices UART and vice versa.
On the settings page one can change the UUID values. The app will remember them but only store them on your device (locally).
We use it for testing our Arduino-like applications.