Getting Started with cURL

Before cURL: What is a Server and Why Do We Need to Talk to It?

A server is simply a computer that:

• Stores data

• Runs applications

• Responds to requests from users

When you open a website:

• Your device sends a request to a server

• The server sends back a response (HTML, JSON, data, etc.)

This request–response communication is the foundation of the web.

What is cURL?

cURL is a command-line tool used to send requests to a server and see the response.

In simple words:

cURL lets you talk to a server from the terminal.

It works with:

• Websites

• APIs

• Backend services

You type a command → server responds → you see the result.

Why Programmers Need cURL

Programmers use cURL to:

• Test APIs

• Check server responses

• Debug backend issues

• Learn how HTTP works

• Verify if a server is up or not

Unlike a browser:

• cURL is fast

• cURL is simple

• cURL shows raw responses

For backend developers, cURL is like a basic testing tool.

Making Your First Request Using cURL

Let’s start with the simplest possible command.

curl https://example.com

What happens here?

• cURL sends a request to example.com

• The server sends back a response

• cURL prints that response in the terminal

This is similar to opening a website — but without a browser

Understanding Request and Response (High Level)

Every communication using cURL follows this pattern:

Request

• Sent by client (you)

• Contains:

  • Method (GET / POST)

  • URL

  • Optional data

Response

• Sent by server

• Contains:

  • Status code (200, 404, etc.)

  • Data (HTML, JSON, text)

Using cURL to Talk to APIs

APIs are servers that return data instead of web pages.

Example:

curl https://api.github.com

You will see:

• JSON data

• Metadata about the API

This is extremely useful because:

• Backend developers work with APIs daily

• cURL helps test APIs quickly without writing code

Introducing GET and POST (Only the Basics)

GET Request

Used to fetch data.

curl https://api.github.com/users/octocat

GET means:

“Give me information”

POST Request

Used to send data.

curl -X POST https://example.com

POST means:

“I want to send something to you”

For now, just remember:

• GET = read data

• POST = send data

Browser Request vs cURL Request

When you open a website:

• Browser sends the request

• Browser formats the response nicely

With cURL:

• You send the request manually

• You see the raw response

This makes cURL perfect for:

• Learning

• Debugging

• Backend testing

Where cURL Fits in Backend Development

In backend and production systems:

• cURL is used to test APIs

• cURL checks server health

• cURL helps debug issues quickly

Even experienced engineers use cURL daily.