If you’re learning programming, web development, or APIs, you’ll hear the word cURL a lot. At first, it might feel intimidating strange commands, terminal windows, and servers you can’t see.
Don’t worry. This guide will walk you through cURL step by step, using plain language and simple examples.
By the end, you’ll understand what cURL is, why programmers use it, and how to make your first request with confidence.
First Things First: What Is a Server?
Before we talk about cURL, let’s understand servers.
A server is just a computer that:
- Stores data
- Runs applications
- Responds when someone asks it for information
Whenever you:
- Open a website
- Log into an app
- Fetch data from an API
You are talking to a server.
Your browser sends a message like:
“Hey server, can you send me this webpage?”
The server replies with:
“Sure, here you go.”
That back-and-forth conversation is the foundation of the internet.
So Where Does cURL Fit In?
Normally, your browser talks to servers for you.
But what if you want to:
- Test an API
- Fetch data without a browser
- Send requests directly from your terminal
That’s where cURL comes in.
In very simple terms:
cURL is a tool that lets you send messages to a server from the terminal.
Think of it like this:
- Browser → sends requests automatically
- cURL → lets you send those requests manually
Why Programmers Need cURL
Programmers use cURL because it helps them:
- Test APIs quickly
- Debug backend services
- See raw server responses
- Work without a browser
- Automate requests
If you’re doing backend development, cURL becomes a daily companion.
Making Your First cURL Request
Let’s start with the simplest possible command.
Open your terminal and type:
curl https://example.com
You just:
- Sent a request to a server
- Asked for a webpage
- Received a response
What Just Happened Behind the Scenes?
When you ran that command, cURL did three things:
- Sent a request to the server
- The server processed it
- The server sent back a response
This is how almost all web communication works.
No flags. No complexity. Just confidence.
Understanding Request and Response
The Request
A request is simply:
- What you want
- Where you want it from
In our example:
- You wanted a webpage
- From example.com
This is called a GET request.
The Response
The response usually contains:
- Status (Did it work?)
- Data (The content returned)
For example:
- 200 OK → Success
- 404 Not Found → Page doesn’t exist
- 500 Server Error → Server had a problem
The text you see printed in the terminal is the data returned by the server.
GET and POST
Let’s keep things simple.
GET
- Used to get data
- You’ve already used it
- Default method in cURL
Example:
curl https://api.example.com/users
POST
- Used to send data to a server
- Common when submitting forms or creating data
Simple example:
curl -X POST https://api.example.com/users
Don’t worry about the details yet, just remember:
- GET = ask for data
- POST = send data
That’s enough for now
Using cURL to Talk to APIs
APIs are just servers that speak in data instead of webpages.
When you use cURL with an API, you might:
- Fetch user information
- Create new records
- Test endpoints before writing code
Example:
curl https://api.example.com/products
The server might respond with JSON instead of HTML and that’s totally normal.
Common Mistakes Beginners Make with cURL
You’re not alone if you hit these early on:
1. Overusing Flags Too Early
cURL has many options, but beginners don’t need most of them.
Start simple. Add complexity later.
2. Forgetting the URL
Yes, it happens
cURL always needs a destination.
3. Confusing GET and POST
- GET → retrieve
- POST → send
4. Panicking Over Ugly Output
Raw responses aren’t always pretty.
That doesn’t mean something is broken.
5. Expecting a Browser-Like Experience
cURL shows data, not design.
No colors, no layout just the truth.
Final Thoughts
cURL isn’t scary, it’s honest.
It shows you:
- Exactly what you send
- Exactly what the server returns
Start small. Stay curious.
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