VisiProx (visualization proxy) is a software breakout box for TCP connections. It is a straightforward and useful debugging tool.

How It Works

Normally, a client connects directly to a server:

[ client ] → [ server listening on hostname:port ]

VisiProx gets inserted in between them:

[ client ] → [ VisiProx listening on hostname1:port1 ] → [ server listening on hostname2:port2 ]

Data travelling in either direction is displayed or logged before being passed on in an unmodified manner. For binary data, an optional hex display is available.

Note: VisiProx is not a packet sniffer; you will have to point your client at it explicitly.


The original VisiProx is a GUI program which displays a single connection at a time.

VisiProx Junior is a faster, non-graphical variation which writes the data directly to log files. It is capable of handling any number of connections simultaneously.

Both versions are written in Java, so they will run on any platform.


VisiProx is free and open source under the LGPL license. The packages include both source code and compiled bytecode. (25kb) (13kb)

Related Links

It is possible to debug SSL-encrypted connections by combining VisiProx with Stunnel.

home · · last updated 2003.02.22