WebSniffer is an intelligence platform in the making that is going to track changes on the web and provide actionable insights to its users. The online tool can currently view HTTP response headers of any web page, do domain name, IP address lookups and provides user’s browser information such as IP address, user agent and more.
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.
ViewHTTPHeaders.com - View HTTP header response for any web page.
Sky Live HTTP Headers - Sky Live HTTP Headers is an open-source browser extension that visually displays HTTP requests and response headers from every website you visit.
HTTP Header Live - Displays the HTTP header. Edit it and send it.
HTTP Header Analyzer - HTTP Header Analyzer is an open-source browser extension that allows you to see and analyze the current HTTP request and response header from the website URL.
HTTP Debugger - Debug HTTP API calls to a back-end and between back-ends. Easy of use, clean UI, and short ramp-up time. Not a proxy, no network issues!