Getting Started with cURL

What is Server?

for understanding the curl we will start with server. So A server is just a computer which is always connected to internet.

This computer:

• stores data

• gives data when we ask

• takes data when we send

For example:

• When we open Google, Google server sends data to us

• When we login somewhere, we send data to server

So whenever we use internet, we are actually talking to servers.

Simple Diagram: How cURL Works

textYour Terminal (cURL)  →  [Message: "Give me data!"]  →  Server
                                      ↓
                          [Reply: "Here's the data + status"]
                                      ↓
Your Terminal (cURL)  ←  Response (status code + data)

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Why do we need to talk to servers?

Because:

• Websites are stored on servers

• Apps get data from servers

• Login, signup, payment — everything needs server

If we cannot talk to server, internet will not work.

Usually browser talks to server for us.
But developers sometimes want to talk directly.

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What is cURL?

cURL is a tool that helps us send message to a server from terminal.

That’s it.

Instead of browser, we use terminal.
Instead of clicking buttons, we type commands.

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Why programmers need cURL?

As a beginner, this is what I understood:

• Browser hides many things

• cURL shows real response from server

• We can test APIs without making website

• We can check if server is working or not

Programmers use cURL because it is:

• fast

• simple

• direct

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My first cURL command

This was the first command I tried:

curl https://example.com

After pressing Enter, I saw a lot of text.

At first I got scared 😅
But then I understood — this is just the response from server.

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What is request and response?

This is very important and simple.

Request

When we ask server for something, it is called request.

Example:

“Give me this webpage”

Response

When server replies, it is called response.

Response contains:

• status (success or error)

• data (page or information)

So flow is like:

You → Server → You

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What does response mean?

Server response has two main things:

1. Status code

It tells what happened.

• 200 means everything is OK

• 404 means page not found

• 500 means server has problem

2. Data

This is the actual content:

• HTML

• JSON

• text

cURL shows this data directly in terminal.

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GET and POST

GET

GET is used to get data.

Example:

curl https://jsonplaceholder.typicode.com/posts/1

This means:

“Server, please give me post number 1”

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POST

POST is used to send data.

POST is used in:

• login

• signup

• forms

Example idea:

curl -X POST https://tesst.com/login

I am not using many flags now because it becomes confusing.
Understanding idea is more important.

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Using cURL to talk to APIs

APIs are also servers, but they send data instead of web pages.

I tried this API:

curl https://jsonplaceholder.typicode.com/posts/1

And I got data like this:

{
  "userId": 1,
  "id": 1,
  "title": "sunt aut facere repellat provident occaecati excepturi optio reprehenderit",
  "body": "quia et suscipit\nsuscipit recusandae consequuntur expedita et cum\nreprehenderit molestiae ut ut quas totam\nnostrum rerum est autem sunt rem eveniet architecto"
}%

This is how apps get data from backend.

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Browser vs cURL (what I feeel)

Browser

• shows design

• hides technical things

• easy for users

cURL

• shows raw data

• no design

• good for learning and testing

Same server, different way to talk.

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Where cURL is used in backend

From what I learned:

• testing APIs

• checking server response

• debugging issues

• learning how internet works

Many backend developers use it daily.

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Final thoughts (from a learner)

I am still learning, but now I am not scared of cURL.

For me:

cURL = talking to server from terminal

If you understand this, you are already doing good.

I will learn more about:

• sending JSON

• headers

• authentication

Maybe I will write next blog also 😊