Sensor-App fro android and ios

We are using iot sensors. Our customers get the fresh sensors, that have a label with a unique id (in digits and as qr-code). The sensor is used to measure data a certain places, the data are transfered to our iot platform, where the data are stored, evaluated,visualized and messages are generated, if certain thresholds are exceeded or a sensor is timed out. To initialize new sensors, to administer the exisiting sensors, to give user access and remove user access to sensors and show timeline of measured data, a smartphone app is needed. The app should run on android as well as on ios. A rough flow chart on how the app should work is shown in the attachment. The project should have at least to phases Phase 1 is to develope an ui for the app Phase 2 is to develope the app An simple API to interact with the iot portal is availble. The app should be delivered with source code in flutter.