How to make a POST request with cURL

Posted 

2 min read

cURL is a command-line utility for transferring data from or to a remote server using one of the supported protocols. It is installed by default on macOS and most Linux distributions.

cURL is used by developers for testing APIs , viewing response headers, and making HTTP requests.

In this article, we’re going to explain how to use cURL to make POST requests. The HTTP POST method is used to send data to the remote server.

Making a POST request

The general form of the curl command for making a POST request is as follows:

curl -X POST [options] [URL]
The -X option specifies which HTTP request method will be used when communicating with the remote server.

The type of the request body is indicated by its Content-Type header.

Generally, a POST request is sent via an HTML form. The data send to the form is usually encoded in either multipart/form-data or application/x-www-form-urlencoded content type.

To create a POST request, use the -F option, followed by the field=value pair. The following example shows how to make a POST request to a form that has “name” and “email” fields:

curl -X POST -F 'name=linuxize' -F 'email=linuxize@example.com' https://example.com/contact.php

When the -F option is used, curl sends the data using the multipart/form-data Content-Type.

Another way to make a POST request is to use the -d option. This causes curl to send the data using the application/x-www-form-urlencoded Content-Type.

curl -X POST -d 'name=linuxize' -d 'email=linuxize@example.com' https://example.com/contact.php

If the -d option is used more than once you can merge the data using the & symbol:

curl -X POST -d 'name=linuxize&email=linuxize@example.com' https://example.com/contact.php

Specifying the Content-Type

To set a specific header or Content-Type use the -H option. The following command sets the POST request type to application/json and sends a JSON object:

curl -X POST -H "Content-Type: application/json" \    -d '{"name": "linuxize", "email": "linuxize@example.com"}' \    https://example/contact

Uploading Files

To POST a file with curl, simply add the @ symbol before the file location. The file can be an archive, image, document, etc.

curl -X POST -F 'image=@/home/user/Pictures/wallpaper.jpg' http://example.com/upload

Conclusion

We’ve shown you how to use curl to make POST requests. For more information about curl, visit the Curl Documentation page.

If you have any questions or feedback, feel free to leave a comment.