Sending HTTP Headers With cURL

• Sending HTTP headers
• Sending custom HTTP headers
• Sending multiple headers
• Get/show HTTP headers
• Advanced tips for working with cURL headers
• FAQ

In this guide, you’ll learn how to send and receive HTTP headers using cURL, a versatile command-line tool for transferring data with URL syntax.

Sending HTTP headers

HTTP headers consist of a name-value pair, separated by a colon – :. The name identifies the type of information sent, while the value is the actual data.

Some of the most common HTTP headers include User-Agent, Content-Type, Accept, and Cache-Control.

When you send an HTTP request with cURL, it sends the following headers by default:

• Host: example.com
• user-agent: curl/7.87.0
• accept: */*

You can change the value of these headers when sending a request.

To send HTTP headers with cURL, you can use the -H or --header option followed by the header name and value in the format "Header-Name: value".

curl -H "User-Agent: MyCustomUserAgent" http://httpbin.org/headers

In the example below, a custom User-Agent header is sent as "MyCustomUserAgent" when requesting the http://httpbin.org/headers page.

The http://httpbin.org/headers page is meant for testing as it returns a JSON file with all the headers it found in the request. Ignore the X-Amzn header that this site uses internally.

Sending custom HTTP headers

To send custom HTTP headers with cURL, use the -H option and provide the header name and value.

curl -H "Authorization: Bearer my-access-token" http://httpbin.org/headers

Sending multiple headers

To send multiple headers with cURL, you can use the -H option multiple times in the same command.

curl -H "User-Agent: MyCustomUserAgent" -H "Accept:application/json" http://httpbin.org/headers

Get/show HTTP headers

To view the response headers from a web server, you can use the -I or --head option with cURL.

curl -I http://httpbin.org/headers
curl --head http://httpbin.org/headers

You can also use the -i or --include option to show both the response headers and the content in the output.

curl -i http://httpbin.org/headers
curl --include http://httpbin.org/headers

Advanced tips for working with cURL headers

Sending empty headers

curl -H "User-Agent;" http://httpbin.org/headers

Removing headers

curl -H "User-Agent:" http://httpbin.org/headers

Verbose mode

If you want to see more detailed information about the request and response, including the headers sent and received, you can use the -v or --verbose option.

curl -v http://httpbin.org/headers
curl --verbose http://httpbin.org/headers

Saving headers to a file

curl -D headers.txt -o content.txt http://httpbin.org/headers

FAQ

How to add headers in cURL?

curl -H "User-Agent: MyCustomUserAgent" http://httpbin.org/headers

Does cURL automatically add headers?

Yes, cURL automatically adds standard headers, such as User-Agent, Accept, and Host, based on the request type and other options. You can override or add custom headers using the -H command.

How to check HTTP headers in cURL?

To check HTTP headers in cURL, use the -I or --head option to only retrieve headers without the actual content.

curl -I http://httpbin.org/headers

Alternatively, you can use the -i or --include option to show both the response headers and content in the output.

curl -i http://httpbin.org/headers

How to send empty headers with cURL?

curl -H "User-Agent;" http://httpbin.org/headers

How to remove a default header in cURL?

To remove a header that cURL adds by default, provide the header name followed by a colon without a value. For example, to remove the User-Agent header:

curl -H "User-Agent:" http://httpbin.org/headers