Getting Started with CURL

Let say you are at your home and you want to eat pizza , you called the restaurant and ordered it , similarly in the world of internet curl does the work of calling 😃.

In simple word = CURL is a tool from which you can talk to internet

1) Why CURL is needed ?

• To talk to website

• To test API

• To check the response of the website/server

• To debug, if any issue

2) CURL Basic Flow

curl chaicode.com

Output can vary:

• HTML code of website

• API response

• Error message

3) Understanding request and response

Request → What you ask

Response → What you get in response of your request

Real World example :

You went to restaurtant and ask for burger its called request , in return you got burger thats response.

Now let’s understand the same via curl

curl https://chaicode.com

In the above example you are requesting to give the data of chaicode.com , that’s called request , and the result which you will get is response.

Request:

Request has 4 items:

REQUEST
--------------------
Method: GET (By Default)
URL: https://example.com
Headers: extra info
Body: (optional)

1) Method (What you want ?)

GET : What you get ?

POST : What you send ?

curl https://chaicode.com

Default method = GET

It means only Read the data.

2) URL

Server Address: https://chaicode.com

3) Headers (Extra info)

Le’t say you said , I want veg burger with extra cheese , that’s what extra information is.

Extra Info === header

curl -H "Accept: application/json" https://chaicode.com

4) Body(Data which you are sending)

Only applicable on POST/PUT

Example:

curl -X POST -d "name=umang" https://chaicode.com

X = To send the data

Normally, curl only sends the data but here by using -X you are sending some data where -d is you data

POST means :

• Login

• Form submit

• Data send

The above command means , server https:/chaicode.com , I am sending you data which is having name=umang , accept it and send me the output

Explaination via diagram

You (curl)
   |
   |  POST request
   |  name=umang
   ↓
Server
   |
   |  Response (JSON)
   ↓
You (Terminal)

Response

Server gives you 3 things

1) Status Code
2) Headers
3) Body

1) Status Code

2) Header (Server Info)

Server sends data , something like below

< HTTP/2 200
< date: Sun, 25 Jan 2026 06:46:54 GMT
< content-type: application/json; charset=utf-8

Trick:

• \> = REQUEST

• < = RESPONSE

CURL example to talk to API:

curl -v https://chaicode.com

O/P:
(REQUEST)
> GET / HTTP/2
> Host: chaicode.com
> User-Agent: curl/8.7.1
> Accept: */*
>
(RESPONSE)
* Request completely sent off
< HTTP/2 200
< date: Sun, 25 Jan 2026 06:50:53 GMT
< content-type: text/html; charset=UTF-8

Diagram

You (curl)
   |
   |  REQUEST (GET chaicode.com)
   ↓
Server
   |
   |  RESPONSE (200 OK + HTML)
   ↓
You (Terminal)

Common mistakes beginners make with Curl

1. Sending POST request to a normal website (Not an API) , like curl -X POST -d "name=umang" https://google.com

2. Not understanding GET vs POST

   1. GET = Fetch data (By Default)

   2. POST = Send data

3. Forgetting headers

   1. curl -X POST -d '{"name":"umang"}' https://api.com is wrong command instead use , curl -X POST -H "Content-Type: application/json" \-d '{"name":"umang"}' https://api.com

4. Wrong URL

5. Not using -v (verbose) to debug

6. Confusing HTTP and HTTPS , like curl http://example.com is wrong , instead use curl https://example.com

7. Forgetting quotes in JSON , like curl -X POST -d {name:umang} https://example.com is worng , instead use curl -X POST -d '{"name":"umang"}' https://example.com , JSON must be properly quoted.

Thank You for reading 🙏🏻