Vansh Panchal

We structured Firestore with a denormalized database design where post metadata and user profile statistics are cached inside the feed document. Additionally, we implemented local state caching using Hive on the mobile app. This allowed immediate visual responses on the feed, reducing Firestore read calls by 45% and keeping feed loads under 200ms by avoiding multi-collection joins.

We utilized a Retrieval-Augmented Generation (RAG) light strategy within the Flutter app. When a user tags the Gemini bot in a post, we programmatically prepend structural context to the REST request payload. This includes system-level grounding prompts, the post description, related tags, and the top 3 most relevant comments. This bounds the model's response envelope, raising the relevancy rate to approximately 85%.

We avoided direct updates to a single user document for XP gains. Instead, we used a write-only subcollection design pattern where every XP event (e.g., post created, answer accepted) writes a lightweight transaction record. A background Firebase Cloud Function periodically aggregates these events to update the main profile's XP and level. This prevents document-lock contention and scales cleanly during simultaneous activity.

DevSphere is a mobile-first developer community where cross-platform reach is critical. Using Flutter allowed us to share 100% of the UI design and network orchestration codebase between Android and iOS. This cut development time in half while maintaining a consistent 60 FPS performance thanks to Flutter's Skia/Impeller rendering engines.