Getting Started with cURL

What is cURL?

cURL stands for Client URL.

It is a command-line tool used to send and receive data using URLs. The powerful part is that you can interact with websites and APIs directly from your terminal or command prompt.

This means:

No browser needed
No HTML or CSS rendering
No UI components required
Just raw communication with servers

Instead of loading a webpage visually, cURL simply prints the response returned by the server.

Because of this simplicity and control, programmers love using cURL.

Why cURL Exists and Why Programmers Use It

Browsers are built for normal users, not developers. So they hide many technical details.

When you open a website in a browser:

You don’t see request headers clearly
You don’t see request methods
Raw server responses are hidden
Payload control is limited
Browser manages cookies and cache automatically

This makes life easy for users, but harder for developers trying to debug issues.

cURL solves this problem by providing:

- Control
- Visibility
- Repeatability
- Automation

Developers can:

Test APIs quickly
Debug backend services
Validate endpoints
Send custom requests instantly

And since cURL works in terminals, it is useful in:

Shell scripts
CI/CD pipelines
Servers without GUI
Automation tools
Cron jobs

Making Your First Request Using cURL

A simple request looks like this:

curl https://google.com

Instead of opening a webpage, cURL prints the server response — typically raw HTML.

Since cURL has no interface, it doesn't render pages visually. It simply outputs the data returned.

Understanding the Request–Response Model

Every interaction on the internet follows a simple pattern:

Client → Request → Server → Response → Client

Before using APIs or advanced cURL commands, understanding this model is essential.

What is an HTTP Request?

An HTTP request is sent by the client (your system using cURL) to a server asking for some resource or action.

A request contains:

Method — action type (GET, POST, PUT, DELETE)
URL — location of resource
Headers — extra information
Body — data sent to server (optional)

Example actions:

GET → Fetch data
POST → Send data
PUT → Update data
DELETE → Remove data

What is an HTTP Response?

After processing the request, the server sends back a response.

A response contains:

Status Code — request result (200, 404, 500, etc.)
Headers — metadata
Body — actual returned data (HTML, JSON, text, etc.)

Example status codes:

200 → Success
404 → Not found
500 → Server error

Browser Requests vs cURL Requests

1. User Experience

Browser requests

Designed for non-technical users
Focus on visuals and interaction
Hide technical complexity

cURL requests

Designed for developers
Show raw server behavior
Great for debugging

2. Request Construction

Browser

Automatically manages cookies and cache
Adds headers automatically
Handles sessions silently

cURL

Sends only what you specify
No hidden behavior
Fully manual control

3. Visibility into HTTP Details