Viewing HTTP Headers of a Website
This is the most valuable and useful tool for web developers and SEO (search engine optimization) people. Understanding correct server status codes is required when working with the sites with many URL rewrites, specially when working with redirects. The redirect response codes such as HTTP 301 (Moved Permanently) are normally cached by the browsers. Therefore you cannot understand the correct server response without this kind of a tool.
View HTTP Headers and Response Contents Tool
This tool can also be used to retrieve the server response content too.
The tool can connect to the website using various types of user agent strings. It includes almost all popular browsers as well as search engines such as Google bot and MSN bot (Bing)
Access the tool
Free and unlimited. Enjoy!