Question 1

What is curl used for?

Accepted Answer

curl (Client URL) is a command-line tool for transferring data using various protocols — most commonly HTTP and HTTPS. Developers use it to test APIs, download files, submit forms, and debug network requests without needing a browser or GUI client.

Question 2

How do I add custom headers to a curl request?

Accepted Answer

Use the `-H` flag followed by the header string: `curl -H "Content-Type: application/json" -H "Authorization: Bearer token" https://api.example.com`. Each `-H` flag adds one header.

Question 3

How do I send a JSON body with curl?

Accepted Answer

Use `-d` or `--data-raw` to provide the body and set the Content-Type header: `curl -X POST -H "Content-Type: application/json" -d '{"key":"value"}' https://api.example.com`.

Question 4

What does the -k or --insecure flag do?

Accepted Answer

The `-k` flag tells curl to skip TLS/SSL certificate verification. This is useful for testing with self-signed certificates but should never be used in production as it makes the connection vulnerable to man-in-the-middle attacks.

Question 5

What is the difference between -L and not using it?

Accepted Answer

The `-L` flag tells curl to follow HTTP redirects (301, 302, etc.). Without it, curl stops at the first response even if the server redirects to another URL. Most REST APIs use it when an endpoint has moved permanently.

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