This guide explains how to obtain information about the presence of a caching system on a website using the curl command.

Introduction

• In the world of programming and system administration, it is often necessary to determine whether a website uses a caching system to improve its performance.
• Caching systems such as Fastly are commonly used to temporarily store data in order to serve it to users more quickly.

Determine if a website uses a caching system

To determine if a website uses a caching system to improve its performance and to understand how websites function and how they can be optimized:

1. Run the following command from a Terminal application (command-line interface, CLI) on your device:
2. curl -svo /dev/null [url] -H “Fastly-Debug: true”
   • Replace [url] with the address of the website you want to check.

If the website uses Fastly or another similar caching system, you will see specific debugging information in the command output. The details provided may include information about HTTP requests and responses, as well as information about the cache and performance.

Using the curl command

curl is a command-line tool used to transfer data using URLs.

The -svo /dev/null option is used to perform a silent request (-s), display detailed information about the request (-v), and redirect the output data to /dev/null to discard it (/dev/null is a special device on Unix/Linux systems that acts like a trash can). -H "Fastly-Debug: true" is an HTTP header added to the request to request specific debugging information from Fastly.