I need a robust mobile application that talks directly to my Raspberry Pi-based device and guides users through a short diagnostic workflow. The same build must run smoothly on both iOS and Android. . Require to be done quickly. Developer should have proper knowledge of mobile app dev as well as able to link the mobile app with RPI as per standard protocols via wifi/Bt. Please note this is a client project hence provide rational quotations. Irrational quotations will be ignored. App flow • Screen 1 – discover, pair and stay connected to the Raspberry Pi. • Screen 2 – present a short questionnaire and store responses locally until upload. • Screen 3 – wait for the device trigger, show the captured image, let users review three separate image sets and confirm each one. • Screen 4 – once the next device trigger arrives, display the sensor values streamed from the Pi in real time. • Screen 5 – collect follow-up diagnosis tags in a second questionnaire. • Screen 6 – push everything from screens 2-5 to an online database, showing progress and success/fail feedback. Authentication A simple email-and-password log-in is mandatory before anyone reaches the pairing screen. Backend I need a lightweight RESTful API that the app hits for sign-up / sign-in, image and sensor data uploads, and any future analytics calls. Please design the endpoints, database schema, and secure token flow; the Pi side already sends its data over the local network once a connection is open. Deliverables • Production-ready source code for the mobile app Flutter • API code with clear documentation and environment files for rapid deployment to a cloud host (AWS, GCP, Azure or similar). • Build instructions plus a short video or screenshots proving the full workflow on both an iPhone and an Android device. The key success criteria are reliable device pairing, instant image preview, lossless data upload and a clean, intuitive UI that feels identical on both platforms. If this matches your skill set, let’s get started right away.