Getting Started with cURL

cURL stands for "Client for URLs" , a command-line tool used to transfer data to or from a server.

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First, what is a server?

A server is just a computer(a machine which is 24×7 available) on the internet that:

• waits for requests

• sends back responses

When you open a website, your browser talks to a server.

You don’t see the conversation.
But it’s happening every time

Servers:

• store websites

• provide data (APIs)

• accept form submissions

• handle logins, payments, uploads

If you are a programmer, you must be able to talk to servers directly, not only through a browser.

That’s where cURL comes in.

What is cURL?

cURL is a tool that lets you send messages to a server from the terminal.

That’s it.

No UI.

No browser.

Just you → terminal → server.

Think of cURL as: “A browser controlled by commands nothing else”.

Why programmers need cURL ?

Because browsers:

• hide details

• auto-handle things

• don’t show raw responses clearly

cURL lets you:

• Test servers quickly

• Talk to APIs

• Debug backend issues

• Understand what’s really happening

• Direct Protocol Interaction

If you work with backend, APIs, or DevOps — cURL is must.

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Making your first request using cURL

1. cURL usually comes pre-installed on macOS, Linux, and Windows 10/11.

Open your Terminal (Mac/Linux) or Command Prompt (Windows) and type:

bash

curl --version

2. The simplest way to use cURL is to fetch a website's content. Type this and hit Enter:

    curl https://www.google.com
   

   What happened? You just received a giant wall of text. That is the HTML code that makes up Google's homepage. Your browser usually turns this code into a pretty page, but cURL shows you the raw data.

3. By running this command, we confirm three things:

   • our computer can reach the server

   • The server responded successfully

   • We received real data from the internet

4. cURL does not:

   • Open a webpage visually

   • Run JavaScript

   • Load images or styles

   It only fetches and displays the response.

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How Does a Request/Response model works?

How Request–Response works (simple view)

1. Client sends a request to the server

2. Server understands what is being asked

3. Server performs the action

4. Server sends a response back

5. Client uses the responseHTTP Methods (What kind of action you are asking for————————————————————————————————————-

When you use cURL or a browser, you are not just contacting a server —
you are also telling it what you want to do.

That instruction is called an HTTP method.

Common HTTP methods (only the important ones)

• GET
  Used to request data
  Example: loading a webpage or fetching API data

• POST
  Used to send data to the server
  Example: submitting a form, creating a new user

• PUT
  Used to update existing data
  Example: updating a user profile

• DELETE
  Used to remove data
  Example: deleting a record

For beginners, remember this:

GET = ask
POST = send
PUT = update
DELETE = remove

• Status Codes: Indicate the outcome of the request (e.g., 200 OK, 404 Not Found). Status codes are short numbers that explain the result.

• Response Headers: Additional information that accompanies the response.

• Response Body: Data returned by the server (e.g., HTML, JSON).