Click on a feature for more information:
HttpWatch captures a wide range of HTTP related data including:
Secure browser sessions that use the HTTPS protocol are displayed in their unencrypted form in HttpWatch, making it easy to debug banking and finance applications.
Starting HttpWatch is simple and easy. An extra icon is added to Internet Explorer and Mozilla Firefox allowing HttpWatch to be opened and started with two mouse clicks:

The log file format used by HttpWatch results in much smaller files that other formats such as XML and contains everything that is displayed in HttpWatch. This includes binary format files and streams, compressed content and network information. If your customers send you HttpWatch log files you will get a full and accurate representation of the HTTP activity in their browser.
A standalone log file viewer allows HttpWatch .hwl files to be viewed and modified outside the browser.
The Summary view can be used at any time to quickly display data about the whole log, a single page or a number of selected items. The following types of data are shown:
Requests are grouped by page as shown below. Each page group can be separately expanded or collapsed to aid navigation through large log files.
Page level time charts are displayed and updated in real-time as you record requests in HttpWatch. This gives a direct, visual indication of how a site is performing - allowing common problems to be diagnosed at a glance:
The time chart displayed for each request is broken down into a number of colored sections to show network level timings such as DNS lookup and TCP connects:
By using HttpWatch Basic Edition, you and your customers can record and view log files without having to purchase extra HttpWatch licenses. Here are two scenarios where you could make use of the free Basic Edition of HttpWatch:
Only one of the parties involved requires a license for HttpWatch Professional. The other party can use HttpWatch Basic Edition free of charge. Please see HttpWatch Basic Edition vs Professional Edition for more detail.
HttpWatch has a comprehensive automation interface that can be used by most programming languages (e.g. C#, Javascript & Ruby). The interface can be used to control the HttpWatch plug-in for IE or Firefox and to access data in HttpWatch log files. If you are already running automated tests, you can integrate HttpWatch and record HTTP level information during your tests. The recorded data that then be checked for certain types of configuration and performance problems (e.g. HTTP compression is not enabled).
The ability to access data in an HttpWatch log file makes it possible to develop custom reports and automate repetitive tasks. The C# code, shown below, exports all javascript files from a log file.

The timing information displayed in HttpWatch is accurate to a a single millisecond (0.001 sec).

HttpWatch supports filtering of requests by wide variety of criteria such as content types, response codes, URLs, headers and content.
HttpWatch works with systems that have HTTP compression enabled, displaying the expanded content and providing information about the compression savings achieved.

Data can be sorted in HttpWatch by clicking on a column heading. The sort order is applied to existing items and used to order new items as they appear.
Whenever a cookie is sent to a web server only its name and value appear in the HTTP request message. HttpWatch also displays the associated domain, path and expiration data making it easier to determine why a particular cookie value is being used. Other HTTP monitoring tools only display this information for cookies in the HTTP response message.

The Overview and Stream tabs show DNS lookups, TCP connects, IP addresses and ports used by an HTTP request. This can help locate network related problems and check that Keep-Alive connections are being used effectively.
The Send and Receive columns show the actual number of bytes that the browser had to send and receive when executing an HTTP request. Other tools just show you the content size, but it is the network level data sizes that really have an impact on performance:

HttpWatch displays the raw HTTP streams sent to and received from a web site:
This low level view of the HTTP protocol helps to show the effect of using technologies such as chunked encoding or compression, and can be useful if you want to reproduce a request programmatically.
HttpWatch shows the interaction between browser and its cache, not just network traffic between the browser and the web site. This is an important feature when a web site is being tuned for performance or to determine why pages are not updating correctly
All commonly used actions in HttpWatch can be invoked with keyboard accelerators, even when the keyboard focus is in another part of the browser's user interface. For example, this menu shows the keyboard accelerators that can be used to control filtering:

The data captured by HttpWatch can be exported in XML or CSV (comma separated variable) formats. Sample log files are available for download:
HttpWatch logs and displays all the intermediate responses caused by the use of techniques such as redirection, authentication and 1xx responses. Some tools just synthesize the response and may show invalid responses (e.g. non zero Content-Length headers on 304 responses). With HttpWatch you see the actual data returned by the web server, even over HTTPS connections.

HttpWatch can be configured to automatically record and save log files with no manual intervention or programming. Log files are written out to a specified directory at regular intervals or when the browser closes:

Text, image and flash based content can be viewed within HttpWatch, exported to another application or saved to a file. The content window uses syntax highlighting on common web formats, such as XML, HTML and CSS:
HttpWatch supports many commonly used character encoding schemes so that it can display the correct international characters:

HttpWatch log files can be printed in HttpWatch Studio or from the browser plug-in:

HttpWatch works with Internet Explorer 6 or 7 and Mozilla Firefox 2.0 or 3.0 on Windows XP, 2003 Server, 2008 Server and Vista (including IE 7 protected mode) . It can be easily installed in a few minutes - No device drivers or proxies have to be configured.
The setup program is simple to run manually, and supports automated deployment by scripts or tools such as SMS.
HttpWatch was the first integrated HTTP sniffer for Internet Explorer and leads the way with a simple, yet powerful, user interface.