How to use Curl

Published on November 14th, 2019

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Curl (Client URL) is command line tool used for transferring data using protocols like http, ftp or smtp. I mostly use it for quick testing of APIs. Curl has a lot of options but I’ll go through most used ones.

Curl is probably already installed on your system. Check it by running:

curl --version

If this command doesn’t return version, install it from its download page.


  • -X POST - specify preferred http method
  • -H "Content-Type: application/json" - add headers to request
  • -b "NAME=VALUE" - add cookie to request
  • -c /path/to/cookie - save cookie to file
  • -d '{"key": "data"} - data for POST request
  • -I - return only headers


  • -o /path/to/file - write output to file
  • -O - write output to new file in current directory
  • -v - provide more informations
  • -# - display progress bar
  • -f - fail silently
  • -k - allow insecure connections