The Layers of Your App

Identify the three core layers of a modern application and the role each plays

Distinguish between code that runs on the user's device and code that runs on a server, and why it matters

Explain why sensitive logic and credentials should never be exposed in the front end

Recognise how vibecoding platforms like Replit and Lovable relate to these layers differently

Describe what the data and service layer includes and how modern infrastructure-as-a-service fits into app architecture