Getting Started with cURL
Hi, I’m Swastisunder 👋 I’m a full-stack web developer focused on building clean, modern, and practical web applications. I work mainly with the MERN stack (MongoDB, Express, React, Node.js) and enjoy turning ideas into real, usable products. Right now, I’m also learning Python and AI/ML, one concept and one project at a time. Always learning. Always building.
Every time you open website inside browser…
your browser sends request to server.
Then server sends response back.
Very simple idea honestly.
Something like this:
Browser → Server → Response
But sometimes developers dont want full browser.
Sometimes they just want directly talk to server.
From terminal.
That is where:
cURL
comes in.
And honestly…
cURL is one of the most useful beginner tools for backend and API learning.
What Is A Server
Before understanding cURL, first we need understand server.
Server is basically computer which waits for requests.
Like:
websites
APIs
apps
databases
When you open:
google.com
your browser sends request to Google's server.
Then server replies with:
HTML
images
data
videos
JSON
Basically server gives you whatever you requested.
Simple thought:
Server is like restaurant kitchen.
You order something.
Kitchen prepares response.
Then sends it back.
What Is cURL
cURL is command line tool used to talk with servers.
Instead of using browser buttons, you manually send requests using terminal.
Simple example:
curl https://google.com
This command tells server:
“Hey server, send me webpage data.”
And server replies directly inside terminal.
Simple thought:
cURL is like talking to server manually without browser UI.
Why Programmers Need cURL
cURL is heavily used by:
backend developers
API developers
DevOps engineers
testers
Because sometimes developers need:
test APIs
debug backend
check responses
send requests manually
Without opening browser again and again.
cURL is:
fast
lightweight
simple
available almost everywhere
And honestly…
once you start backend development, you will use cURL a lot.
Your First cURL Request
Lets make first request.
Command:
curl https://example.com
What happens internally:
Your Terminal
↓
cURL
↓
Server
↓
Response
Server sends webpage data back.
Usually HTML.
Something like:
<html>
<body>
Example Website
</body>
</html>
Which browser normally renders visually.
But terminal just prints raw response.
Understanding Request And Response
Internet communication mostly works using:
Request → Response
Very simple idea.
Request
Request means:
“Hey server, give me something.”
Example:
curl https://api.github.com
Response
Response means:
“Okay. Here is your data.”
Server sends back:
status
headers
data
Sometimes JSON.
Sometimes HTML.
Sometimes error.
Understanding Status Codes
Every server response contains status code.
Common examples:
| Status Code | Meaning |
|---|---|
| 200 | Success |
| 404 | Not Found |
| 500 | Server Error |
Simple thought:
200 = everything good
404 = page missing
500 = server broke internally
Using cURL With APIs
One of biggest use cases of cURL is APIs.
API means:
Application Programming Interface
Which is basically way for apps to communicate.
Example request:
curl https://jsonplaceholder.typicode.com/users
Response:
[
{
"id": 1,
"name": "Leanne Graham"
}
]
Now server is returning JSON data instead of webpage.
This is how frontend and backend communicates in real applications.
GET Requests
By default, cURL sends:
GET Request
GET means:
“I only want to fetch data.”
Example:
curl https://api.github.com
Very simple.
Fetch data only.
POST Requests
POST means:
“I want to send data to server.”
Example:
curl -X POST https://example.com
POST is commonly used for:
login
signup
forms
creating data
Simple thought:
GET = give me data
POST = take my data
Browser Request vs cURL Request
Normally browser does many extra things:
renders webpage
loads CSS
loads images
executes JavaScript
But cURL only sends request and shows response.
Simple comparison:
| Browser | cURL |
|---|---|
| Visual UI | Terminal |
| Loads full webpage | Shows raw response |
| User friendly | Developer friendly |
| Heavy | Lightweight |
Common Beginner Mistakes
Forgetting URL
Wrong:
curl
Server address missing.
Confusing GET And POST
Beginners sometimes sends POST when they only need GET.
Remember:
GET = fetch
POST = send
Thinking cURL Is Browser
cURL does not render webpages visually.
It only shows raw server response.
Panicking After Seeing HTML
When beginners runs:
curl https://google.com
terminal prints huge HTML mess.
That is normal honestly.
Browser normally converts that HTML into proper webpage.
Real World Backend Usage
Backend developers uses cURL for:
testing APIs
debugging backend
checking authentication
verifying server responses
learning HTTP
Even many production systems internally works using same request-response idea.
So learning cURL also helps understand:
APIs
backend systems
HTTP
networking
Full cURL Flow Diagram
Terminal
↓
cURL
↓
Server
↓
Response
↓
Terminal Output
Very simple flow.
But extremely important for backend development.
Summary
| Concept | Meaning |
|---|---|
| Server | Computer serving requests |
| cURL | Tool to talk with servers |
| Request | Asking server for something |
| Response | Server reply |
| GET | Fetch data |
| POST | Send data |
| API | Communication system between apps |
| Status Code | Response result |
Useful Beginner Commands
# Simple webpage request
curl https://example.com
# API request
curl https://api.github.com
# Fetch JSON data
curl https://jsonplaceholder.typicode.com/users
# Simple POST request
curl -X POST https://example.com
Final Thoughts
At first…
cURL feels very boring.
Just terminal commands.
Nothing fancy.
But internally…
cURL teaches one of the most important ideas in backend development:
Request → Server → Response
Which is basically foundation of modern web.
Websites.
APIs.
Mobile apps.
Cloud systems.
Everything depends on this communication model.
And honestly…
once you start understanding cURL, backend development suddenly starts making much more sense.
