How to Use cURL to Show HTTP Response Headers (With Examples)

Understanding how to use cURL to show response headers is a useful skill when working with web servers, APIs, or debugging tools. Inspecting HTTP headers helps you see what’s happening behind the scenes during communication between a client and a server.

Here, you will learn how to use the cURL command to display response headers, understand how different options behave, how to troubleshoot common issues, and more.

Basic cURL Commands to Show Headers

The cURL tool is widely used to transfer data using URLs. One of its main strengths is the ability to display HTTP response headers quickly and clearly while also being available on nearly any OS by default. Here are several basic commands that you need to know.

curl -I https://iproyal.com

This command sends a HEAD request to the server. In other words, it fetches the headers only (without the response body). Here’s what the output looks like:

HTTP/1.1 200 OK
Date: Wed, 30 Jul 2025 12:34:55 GMT
Content-Type: text/html; charset=utf-8
Connection: keep-alive
CF-RAY: 9674e496587b0206-WAW
Cache-Control: public, max-age=7200
last-modified: Wed, 30 Jul 2025 10:26:39 GMT
strict-transport-security: max-age=15724800; includeSubDomains
x-frame-options: SAMEORIGIN
x-content-type-options: nosniff
x-xss-protection: 1; mode=block
content-security-policy: frame-ancestors 'self';
CF-Cache-Status: REVALIDATED
Report-To: {"endpoints":[{"url":"https:\/\/a.nel.cloudflare.com\/report\/v4?s=mNBLzPFwKZ2iPTz5c%2BCxZTbSjJr%2Fs4EzMytrshax4KoHfYcwY7DT%2BUsfkDGE94AJpC%2FyjmZZzWFwby7eBn5uI7v0f4VCKpI9TSe3T3PD9m9oljKGDAdG0EpYAGXG"}],"group":"cf-nel","max_age":604800}
NEL: {"success_fraction":0,"report_to":"cf-nel","max_age":604800}
Server: cloudflare
alt-svc: h3=":443"; ma=86400
server-timing: cfL4;desc="?proto=TCP&rtt=46245&min_rtt=23442&rtt_var=24209&sent=5&recv=6&lost=0&retrans=0&sent_bytes=3127&recv_bytes=640&delivery_rate=145268&cwnd=252&unsent_bytes=0&cid=8504c0afb5702278&ts=96&x=0

This is a clean and efficient way to view only the response headers. Keep in mind that the symbol in the command is uppercase ‘i’, not lowercase ‘L.’

curl -v https://iproyal.com

This command makes a complete GET request . The -v flag enables verbose mode and shows both request headers sent and HTTP headers received. Here is the output excerpt:

> GET / HTTP/1.1
> Host: iproyal.com
> User-Agent: curl/7.68.0
> Accept: */*
< HTTP/1.1 200 OK
< Content-Type: text/html; charset=UTF-8
< Content-Length: 1256

Notice that the lines starting with ‘>‘ are request headers, and the lines starting with ‘< ‘ are response headers. It shows more details, but also includes the response content unless you decide to filter it.

curl -s -D - https://iproyal.com

This version uses three flags:

• -s. Silent mode, removes progress meter.
• -D -. Dumps headers to stdout.
• No -I (uppercase ‘i’). Includes both headers and returned content.

This approach is useful if you want to capture headers while still seeing the full response.

Comparing Flags

If you use redirection (301 or 302), keep in mind that cURL won’t show the full chain unless you use -L.

cURL Header Troubleshooting Tips

When response headers don’t show up as intended, it can be confusing, but it’s usually easy to fix:

• Check if you’re using the -I (uppercase ‘i’) flag.
• If using -v, scroll past the response content to see headers.
• Use -D to dump headers into a file or stdout.

Also, try checking the cURL version. Older versions might not support newer protocols or header formatting.

Dealing With HTTPS

Sometimes HTTP headers are hidden due to SSL issues. To fix that, try this:

curl -v - `insecure https://iproyal.com`

It tells cURL to ignore SSL certificate validation. It’s especially useful for testing on local servers. Note that full flags (e.g., insecure) are preceded by double dashes (--).

cURL Command Cheat Sheet

• View headers only. curl -I https://iproyal.com
• Save headers to a file. curl -D headers.txt https://iproyal.com
• View verbose response. curl -v https://iproyal.com
• Show headers and response body. curl -i https://iproyal.com
• Show headers with silent output. curl -s -D - https://iproyal.com
• Follow redirects with headers. curl -IL https://iproyal.com
• Use a custom user agent . curl -A 'MyBot/1.0' https://iproyal.com
• Add client headers manually. curl -H X-Test: 123 https://iproyal.com
• Use with a proxy . curl -x http://proxy:port https://iproyal.com

You can also chain multiple requests in a script to automate header checks. If you’re into scraping, we’ve covered it in our article about cURL proxy scraping examples .

Conclusion

Using cURL to view HTTP headers is a simple but effective way to debug and monitor web traffic. It gives complete control when sending HEAD requests, inspecting a response body, or customizing your user agent.

If you combine it with tools like proxies or saved headers, it will give you even more options. You can find more information about cURL in some of our other articles:

• How to download files with cURL
• How to send a cURL POST request
• How to use cURL for basic authentication

FAQ

curl -s -o /dev/null -w '%{size_header}\n' https://iproyal\.com