curl

curl — fetch a URL from the command line. It is one of the commands you type in a terminal, and everything below is produced by running it: the output, the error you get when it goes wrong, and a terminal you can type it into yourself.

What it prints

Run against a small demo project — the same one you get in the terminal below, so the output is what you will see, not an illustration of it.

$ curl https://api.anthropic.com/v1/messages -H "x-api-key: $KEY" -d '{…}'
{
  "id": "msg_01Sim2Z2C",
  "type": "message",
  "role": "assistant",
  "model": "claude-sonnet-4-6",
  "content": [
    {
      "type": "text",
      "text": "Hi! I'm Claude. How can I help?"
    }
  ],
  "stop_reason": "end_turn",
  "usage": {
    "input_tokens": 12,
    "output_tokens": 9
  }
}

Break this command down, word by word →

Learn for free Try it in the terminal

Other commands

pwd ls cd mkdir touch cat

Try it yourself

Same files as above. Nothing here can break, and nothing leaves your browser.

Written by Mikhail Kuzmitskii