Fiddler is a free but powerful tool for monitoring HTTP/HTTTPS traffic between the user's computer and the Internet. It is addressed mainly to creators of web sites and web applications. The program is compatible with any proxy application, so it can easily handle web browsers such as Internet Explorer, Opera, Chrome, Firefox and Safari.

It can debug traffic executed on various operating systems (including the most popular ones, such as Windows, Linux or Mac) and from and to many different programs (e.g. Microsoft Office). If you have multiple devices connected via Wi-Fi, you can use Fiddler to transfer traffic-related data from them.

These are smartphones and tablets based on Android, iOS, Windows Phone and Windows RT operating systems. When capturing information about network activities, Fiddler allows you to display information about session status, header, cache, cookies, links, protocol, compression type and redirections. Nothing stands in the way of filtering the acquired data, conducting in-depth analysis and even archiving it for later reconstruction.

It is worth mentioning that Fiddler enables performance tests, thanks to which the user can obtain information about the "weight" of a given website, as well as take advantage of the option of "flagging" the so-called bottlenecks responsible for data transmission downtime. Fiddler contains many different personalization options that allow you to create rules using Java Script and introduce new functions into the program. More demanding customers will be happy to know that this tool can be expanded by installing various add-ons.