How I Built a Multi-Sport AI Coach on iOS as a Solo Developer — Architecture Decisions That Actually Mattered

Most articles about building AI apps focus on the model. This one focuses on everything around the model — the architecture decisions that determined whether the product would actually ship, actually perform, and actually retain users. SportsReflector is an AI coaching app that analyzes athletic form across 22 sports and every common gym exercise. It uses on-device pose estimation to extract body landmarks from video, calculates biomechanical metrics against sport-specific benchmarks, and return