What is cURL?

cURL, which stands for client URL, is a command-line tool that developers use to transfer data to and from a server. It supports several different protocols, including HTTP and HTTPS, and runs on almost every platform1. This makes cURL ideal for testing communication from almost any device (as long as it has a command line and network connectivity) from a local server to most edge devices1.

The most basic command in cURL is curl [URL]. The curl command is followed by the URL, from which we would like to retrieve some kind of data1. In this case, it would return the HTML source for the specified URL.

Now, to use cURL with REST APIs, you can use different HTTP methods like GET, POST, PUT, DELETE, etc. Here are some examples:

1. GET Request: This is used to retrieve data from the server. The command would look like this:

   curl http://api.example.com/resource

2. POST Request: This is used to send data to the server. Here’s an example where we’re sending JSON data:

   curl -X POST -H "Content-Type: application/json" -d '{"key":"value"}' http://api.example.com/resource

3. PUT Request: This is used to update existing data on the server. An example would be:

   curl -X PUT -H "Content-Type: application/json" -d '{"key":"value"}' http://api.example.com/resource/id

4. DELETE Request: This is used to delete existing data from the server. Here’s how you can do it:

   curl -X DELETE http://api.example.com/resource/id

In these examples, -X is used to specify the HTTP method, -H is used to specify request headers, and -d is used to send data in the request body.

Remember, the actual commands may vary based on the API’s specifications. Always refer to the API documentation for accurate information.

Key CURL Resources

• The Tutorial from the official cURL website

  • https://curl.se/docs/tutorial.html

• The open source cURL book from the Everything cURL website

  • https://everything.curl.dev/index.html