# Getting Started with cURL ## 1\. What a **server** is and why we need to talk to it Server is computer that stores data and sends data when we ask. we talk to get websites, apps and files. Example : Ordering food from the kitchen the server is the kitchen you are the customer and your request gets a response. ## 2\. What is cURL curl is command line tool that let’s your computer talk to the servers and get the data from the internet. * we can use it to fetch websites download files or test API’s. * It works with many protocols like HTTP, HTTPS, FTP and many more. Example; ```bash curl ``` This command fetches the webpage from the server and shows it in your terminal. ## 3\. Why programmers need cURL Programmers use curl to talk to servers directly without browser. * Test API’s and see responses in real time * download files and data quickly * debug requests by checking headers curl help programmers interact with servers, test apps and debug efficiently ## 4\. Understanding Request and Response with curl when we use the curl we are basically sending a request to server and receiving a response. A. Request - Your Computer asks server for something Example’ ```bash curl ``` Here the request is please give me the webpage of the [chaicode.com](http://chaicode.com) . B. Response - Server replies with response. Response has three main parts: 1. Status code : Tells request work or failed. * 200 OK - Everything is fine, request sucessed. * 404 Not Found - Server couldn’t find what you asked for. * 500 Internal Server Error - Something went wrong on the server. 1. Headers : Metadata about the response. Example content type (text/html), server name , cookies. Tell your computer how to interpret data. 1. Data / Body - Actual content which we want. Example , HTML of website, JSON from API. Example : ```bash curl -i ``` * \-i shows both headers and body. ## 5\. GET and POST : The Two Most Important Requests When we talk to the server we use two main important requests : GET and POST 1. GET Request GET request is used to ask for data from a server. ```bash curl ``` Use GET when you want to open website, fetch data from api and read information. 1. POST Request POST request is used to send data to the server. ```bash curl -X POST -d "name=Tejas" ``` Use POST when you want to submit the form, send login details. ## 6\. Using cURL to talk to APIs API is just a server that gives data in a structured format. Example : get current weather ```bash curl "" ``` It sends request to weather API and server responds with weather data in JSON. ```bash {"latitude":28.625, "longitude":77.25, "generationtime_ms":0.054955482482910156, "utc_offset_seconds":0, "timezone":"GMT", "timezone_abbreviation":"GMT", "elevation":224.0, "current_weather_units":{"time":"iso8601", "interval":"seconds", "temperature":"°C", "windspeed":"km/h", "winddirection":"°", "is_day":"", "weathercode":"wmo code" }, "current_weather": {"time":"2026-01-30T09:15", "interval":900, "temperature":18.4, "windspeed":6.8, "winddirection":302, "is_day":1, "weathercode":3}} ``` This is exactly how weather websites , mobile weather apps gets their data. ## 7\. Common mistakes beginners make with cURL 1. Forgetting to save output you run ```bash curl ``` use -o to save it ```bash curl -o page.html ``` 1. Mixing get and post Remember this get for reading the data and post for sending the data. 1. Not quoting URL’s special characters break the commands. wrong ```bash curl ``` right ```bash curl "" ``` 1. Forgetting the method flag Sending data without the -x POST wrong ```bash curl -d "name=Tejas" ``` right ```bash curl -X POST -d "name=Tejas" ``` ## 8\. Final Thought curl may look simple but shows how internet really works. No UI just computer and server talking through request and response. Once you understand the curl you don’t just use API’s you understand them because behind the scenes they’re all just doing what curl does.