ViewHTTPHeaders.com - View HTTP header response for any web page.
WebSniffer - WebSniffer is an online tool to outlook HTTP request and response headers.
Live HTTP Headers - The goal of this project is to adds information about the HTTP headers in three ways:
Modify Header Value (HTTP Headers) - Modify Header Value (HTTP Headers) is a browser extension that allows you to add, modify or remove a header for any request to your preferred domains.
HTTP-Repeater (HTTP/s Live Headers) (Beta) - HTTP-Repeater (HTTP/s Live Headers) (Beta) is a browser extension that lets you capture browser requests and repeat the process in a loop automatically.
HTTP Header Spy - HTTP Header Spy is a browser extension that allows you to inspect the request and response header of any website URL.