monline

"HttpWatch is an integrated HTTP sniffer for IE and Firefox that provides new insights into how your website loads and performs."

In short: it integrates with the browser (currently Firefox and IE are supported) at a quite low level and monitors precisely how each network resource is loaded and processed (with timings and all) during the rendering of a webpage. It's partly similiar to the Net tab of Firebug, but provides a few extras that might be worth for you to buy this app (since HttpWatch is a commercial product). And for IE you've no full Firebug (just Firebug Lite) so this brings quite a tool to IE developers.

I've already written about a number of web debugging proxies (Charles, Fiddler, Paros) and now I've stumbled on another one. TCP Catcher comes as a simple JAR (yes, this one is written in Java too, just like Charles) and has a lot less features than Fiddler or Charles. However less is sometimes more. It consists of only two screens: settings page and request (TCP or HTTP) list. It's very easy and fast to set up and works quite well. If you don't need the rich feature set of Charles, TCP Catcher is the way to go.

"tcpmon is an open-source utility for monitoring the data flowing on a TCP connection. tcpmon is used by placing it in-between a client and a server. The client is made to connect to tcpmon, and tcpmon forwards the data to server along-with displaying it in its GUI."

Theoretically the above link takes you to the most recent version of tcpmon. However the project started as an Apache tool. At tcpmon.dev.java.net you can get v1.1 and at ws.apache.org v1.0. But the two are not identical featurewise! The new version lacks the ability to switch between horizontal and vertical layout and more importantly it lacks the XML rendering mode. The latter displays XML content structured, ie. the various nodes are indented based on their level in the XML tree. Unfortunately the old version uses some fixed size font which gets pretty much unreadable at higher resolutions.

WebScarab is a framework for analysing applications that communicate using the HTTP and HTTPS protocols. It is written in Java, and is thus portable to many platforms. WebScarab has several modes of operation, implemented by a number of plugins. In its most common usage, WebScarab operates as an intercepting proxy, allowing the operator to review and modify requests created by the browser before they are sent to the server, and to review and modify responses returned from the server before they are received by the browser. WebScarab is able to intercept both HTTP and HTTPS communication. The operator can also review the conversations (requests and responses) that have passed through WebScarab.

I have been looking for a cross-platform replacement for Fiddler for some time now. Today I stumbled upon Paros, which was written in Java and therefore should run on most Java-capable platforms without modification. Paros is not on par with Fiddler's feature set (and its development has been stalled for the last two years), but it's good enough for capturing/monitoring HTTP traffic on both Linux and Mac OS X.

Charles was my choice of debugging proxy before Fiddler got worked out properly. The initial versions of Charles offered a lot more options, than the initial version of Fiddler. Today both are very feature rich and I'd suggest both to anyone. There're small details that might make you go with one or the other, but basically both are worked out quite well. Charles seemed to be abandoned for a long time (at least I remember that there was not much development at the time I discovered it many years ago), but since v2.x came out development is rolling again. Probably Charles has more features than Fiddler (at least this used to be the case with MS products and their competition ... and with time MS buys out the competition or just bankrupts them via marketing war or other means).

Fiddler is one of the few good software from Microsoft that I know (actually I don't remember whether this was an MS project right from the start or did they just simply buy out the developer company). It works only on Windows and recent versions require .NET, but it's nothing one cannot live with. It is feature rich, supports a lot of views of HTTP sessions, supports various methods for HTTPS traffic capturing, etc. This is one of the best HTTP debugging tools for use on the Windows platform.

There's a list of links pointing to various free, anonymous HTTP proxy directories at OpenDirectory. Might come handy, when you have to test a website from various external addresses.