For guidance on setting up and submitting this assignment, refer to the Marcy lab School Docs How-To guide for Working with Short Response and Coding Assignments.
You’ve been given a diagram (see above) showing the three core layers of a fullstack application:
- Frontend – a React application that users interact with
- Backend – an Express server that handles logic and communication
- Database – a PostgreSQL database that stores persistent data
Imagine you’re explaining how these layers work together by using a real-world example: Instagram.
Your task:
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Explain how Instagram works using the three-layer diagram (or how you think it could work).
- What happens when a user opens the app, scrolls through their feed, likes a post, or uploads a new photo?
- Walk through how data flows from the frontend to the backend and to the database—and back again.
-
Come up with an analogy to help someone new to coding understand these layers.
- You might compare the system to something like a restaurant, a library, or even a post office—anything that helps make the roles of each layer intuitive.
- Make sure your analogy maps clearly to the roles of the frontend, backend, and database.
- Reflect on the value of this separation.
- Why do we separate concerns into these layers?
- What would go wrong if we tried to do everything in one layer?
Audience: Imagine you're writing this for someone who's just starting out in web development and wants to understand how modern apps work.
Length: Around 400–600 words.