Getting Started with cURL: Talking to Servers from Your Terminal
When you open a website in your browser, your browser sends a request to a server. The server responds with data. But what if you want to talk to a server without a browser?
What if you want to:
Test an API
Debug a backend
Check a server response
Send data manually
That’s where cURL comes in.
In this article, you’ll learn:
What cURL is (in very simple terms)
Why programmers need it
How to make your first request
What request and response mean
How to talk to APIs using cURL
Common beginner mistakes
Let’s start from the basics.
What Is a Server?
A server is a computer that:
Stores data
Runs applications
Responds to requests from clients
When you visit:https://example.com
Your browser sends a request to a server.
The server replies with:
HTML
JSON data
Images
Files
This is called client–server communication.
What Is cURL?
cURL stands for: Client URL
In simple terms: cURL is a tool that lets you send requests to a server from your terminal. Instead of using a browser, you use a command line.
Why Programmers Need cURL
Developers use cURL to:
Test APIs
Debug backend services
Check HTTP responses
Send data to servers
Automate server communication
It is especially useful in:
Backend development
DevOps
API testing
cURL helps you see exactly what the server sends back.
Making First cURL Request
Let’s try the simplest possible command.
In your terminal, type:
curl https://example.com
Press Enter.
You will see raw HTML output printed in your terminal.
What just happened?
cURL sent an HTTP request.
The server responded with HTML.
cURL printed that response.
That’s it. You just talked directly to a server.
Understanding Request and Response
When using cURL, two main things happen:
Request
The message sent to the server.
Example:
GET / HTTP/1.1
Host: example.com
This means: “Please give me the homepage.”
Response
The server replies with:
HTTP/1.1 200 OK
Content-Type: text/html
Followed by the actual HTML content.
What Does "200 OK" Mean?
HTTP status codes tell you what happened.
200 → Success
404 → Not Found
500 → Server Error
When using cURL, you are seeing the raw response that browsers normally hide.
Using cURL to Talk to APIs
APIs usually return JSON instead of HTML.
Example:
curl https://jsonplaceholder.typicode.com/posts/1
You will see:
{
"userId": 1,
"id": 1,
"title": "...",
"body": "..."
}
This is API communication. Instead of rendering a webpage, the server sends structured data.
GET vs POST
Let’s keep this simple.
GET
Used to retrieve data.
Example:
curl https://jsonplaceholder.typicode.com/posts
This fetches data.
POST
Used to send data to the server.
Example:
curl -X POST https://jsonplaceholder.typicode.com/posts
This tells the server: “I want to create something.”
Browser vs cURL
Browser renders visuals. cURL shows raw data.
Basic HTTP Structure
Request:
GET /resource HTTP/1.1
Host: api.example.com
Response:
HTTP/1.1 200 OK
Content-Type: application/json
{ "data": "value" }
Where cURL Fits in Backend Development
When building APIs, you often need to:
Test endpoints
Check if server is running
Validate responses
Debug errors
Instead of opening a browser, you use: curl
It’s faster and more precise. Backend developers use it daily.
Common Mistakes Beginners Make
Forgetting https://
Wrong:
curl example.com
Better:
curl https://example.com
Confusing GET and POST
GET retrieves data.
POST sends data.
Expecting Pretty Output
cURL prints raw output. If it looks messy, that’s normal.