Member-only story

HTTP and REST API Design - How Frontend and Backend Systems Communicate 005

Kenuka Karunakaran

12 min read7 hours ago

Press enter or click to view image in full size Cover Image

From understanding the web to designing and engineering scalable software systems.

Not a Medium Member? Friend Link Here!

1. From JavaScript Execution to System Communication

In Day 04, we explored how JavaScript handles asynchronous operations using Promises, async/await, and the event loop. We also introduced the fetch() API, which allows JavaScript to communicate with external services.

But consider this:

When a user clicks Add Task , JavaScript sends a request to a backend. The backend receives it, processes the information, interacts with a database, and returns a response.

How does the frontend know what to send?

How does the backend know what operation to perform?

How do both systems agree on the structure of the data?

They communicate using established protocols and API contracts.…