Getting Started with cURL: Sending Messages to the Internet

Source: Dev.to

What is cURL (In very simple terms)

cURL stands for Client URL. Think of it as a web browser that has no buttons, images, or colors. It’s a command‑line tool that lets you send and receive data from a server using a URL.

If a browser is like a TV where you see everything, cURL is like a walkie‑talkie: you send a specific request to a server, and it sends back a response in plain text.

Why programmers need cURL

• Speed – typing a command is faster than opening a browser and clicking through menus.
• Automation – you can write scripts to call a server hundreds of times in a row.
• Testing APIs – check if the backend (the hidden logic of an app) works correctly before the frontend (the UI) is built.

Making your first request using cURL

Open your terminal (Command Prompt, PowerShell, or any shell) and run:

curl https://www.google.com

You just asked Google’s server for its homepage. Instead of a rendered page, you receive the raw HTML code that the browser would normally turn into a pretty webpage.

Understanding Request and Response

Every cURL interaction consists of two parts:

• The Request – what you send (URL, method, headers, etc.).
• The Response – what the server sends back, typically containing:
  • Status Code – e.g., 200 OK (success), 404 Not Found (missing resource).
  • Body – the actual data (HTML, JSON, etc.).

Using cURL to talk to APIs

The GET Request (asking for data)

curl https://jsonplaceholder.typicode.com/posts/1

The server returns a JSON object representing a single “post.”

The POST Request (sending data)

curl -X POST https://jsonplaceholder.typicode.com/posts -d "title=MyNewPost"

You’ve pushed new information to the server.

Common mistakes beginners make

• Forgetting the protocol – always include https://. curl google.com may fail.
• Invisible characters – copying from rich‑text sources can introduce “smart quotes” (“ ”) instead of straight quotes (").
• Ignoring errors – add -v (verbose) to see the full conversation:

curl -v https://google.com

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