An introduction for full‑stack developers to AR and VR: explains how AR overlays the real world while VR builds fully virtual spaces; showcases uses in gaming, education, retail, and healthcare; outlines core tools (ARKit, ARCore, Unity, Unreal) and design pillars (storytelling, interactivity, 3D audio); previews more accessible, creative futures and new business models; and highlights a virtual art gallery as a flagship project.