Getting Started with cURL: Talking with Servers from the Terminal
Imagine you walk into a restaurant.
You don’t go into the kitchen to cook your food. Instead, you give your order to the waiter. The waiter takes your request to the kitchen and brings back your food.
In the world of the internet:
You are the client
The kitchen is the server
The waiter is cURL
cURL helps you send requests to servers and receive responses — directly from your terminal.
Let’s understand this step by step.
What is cURL?
cURL is a tool that lets you talk to servers from your terminal.
It allows you to:
Fetch webpages
Talk to APIs
Send data to servers
Test backend systems
Think of cURL as a messenger between you and the internet.
Instead of using a browser, you can use cURL to communicate directly.
Why Programmers Need cURL
Browsers hide many technical details.
But developers need more control.
They use cURL to:
Test APIs
Debug backend systems
Check server responses
Automate requests
Verify if servers are working
For example, instead of opening a browser, a developer can simply type a command to get data.
This makes development faster and easier.
Understanding Servers First
A server is a computer that stores data and responds to requests.
For example:
Google's server gives search results
YouTube server gives videos
Instagram server gives posts
When you open a website, your browser sends a request to the server.
The server responds with data.
cURL does the same thing — but from the terminal.
Making Your First cURL Request
Let’s try a simple command:
curl https://example.com
What happens here?
Step-by-step:
cURL sends a request to example.com
The server receives the request
The server sends back a response
cURL shows the response in your terminal
You will see HTML content printed.
This is the webpage data.
Understanding Request and Response
Every communication has two parts:
1. Request (You → Server)
You ask for something.
Example:
“Give me the homepage.”
2. Response (Server → You)
Server replies with data.
Example:
“Here is the homepage.”
This is called the request-response cycle.
Real-Life Analogy
Think of ordering food online.
Request:
You order pizza.
Response:
The restaurant delivers pizza.
cURL = placing the order
Server = restaurant
Response = pizza
Using cURL with APIs
APIs allow applications to communicate.
cURL helps developers test APIs easily.
Example:
curl https://jsonplaceholder.typicode.com/posts/1
Response:
{
"userId": 1,
"id": 1,
"title": "...",
"body": "..."
}
This is data returned by the server.
Developers use this to test applications.
Understanding GET Request
GET is the most common request.
It means:
“Give me data.”
Example:
curl https://api.github.com
This fetches data from GitHub.
Your browser also uses GET when opening websites.
Understanding POST Request (Sending Data)
POST means sending data to server.
Example:
curl -X POST https://jsonplaceholder.typicode.com/posts
This sends data to the server.
POST is used when:
Creating accounts
Sending forms
Uploading data
How cURL Works Internally
Flow:
You → cURL → Server → cURL → You
Idea:
Terminal → cURL → Server
Terminal ← Response ← Server
Step-by-step:
You type command
cURL sends request
Server processes request
Server sends response
cURL shows response
Browser vs cURL
Browser:
Has UI
Shows formatted pages
Easy for users
cURL:
Terminal-based
Shows raw data
Used by developers
A browser is like a car.
cURL is like the engine control system.
Common Mistakes Beginners Make
Mistake 1: Thinking cURL is only for websites
It is also used for APIs, backend testing, and automation.
Mistake 2: Being afraid of terminal
cURL is simple once you try it.
Start with basic commands.
Mistake 3: Expecting visual output
cURL shows raw data, not formatted pages.
This is normal.
Why cURL is Important for Backend Developers
Backend developers use cURL to:
Test APIs
Debug errors
Check server status
Automate tasks
It helps developers understand how systems communicate.
Real-World Example
When you log into Instagram:
App sends a request
Server verifies login
Server sends response
The app shows your profile
Developers use cURL to test this process.
Where cURL Fits in Backend Development
cURL is used in:
Backend development
API testing
DevOps
Debugging
Automation
It is one of the most important developer tools.
cURL is a powerful tool that allows you to communicate with servers directly from your terminal.
It helps developers:
Send requests
Receive responses
Test APIs
Debug systems
Think of cURL as your direct communication line with the internet.
Once you learn cURL, you understand how the web works behind the scenes.
And that’s when you start thinking like a real developer.