Projeto Conecta: Engineering a Closed-Loop, Multi-Profile Local Marketplace with Flutter and Firebase

This work presents the design, engineering and iterative development of Projeto Conecta, a multi-profile mobilemarketplace that connects local merchants, self-employed service providers and consumers in a single, secure digital environment.The application uses Flutter (Dart) on the front end and Firebase (Firestore, Authentication and Storage) on the back end, withrole-based permissions and real-time data synchronization. Three core business rules shape the product: an ecosystem shield thatblocks external links and contacts to prevent off-platform transactions, a smart cart that restricts each order to a single store andpersists across sessions, and a dynamic stock visibility policy that shows consumers only “Available” or “Sold out”. Developmentfollowed agile sprints, from stabilization (Firestore security rules, error handling, guest mode), through checkout refinement (PIXpayment, cash-change validation, real-time order tracking, pickup option, mandatory cancellation justification), to customizationand support (in-app administrator chat, coupons, add-ons, configurable delivery fees, photo uploads, localized error messages).The evaluation is qualitative and based on direct feedback from the target audience during the semester cycle; no quantitativeusability or performance metrics were collected at this stage.