Socket45 is a web browser plug-in "container". It implements a large portion of the Netscape plug-in interface, and is capable of running most browser plug-ins.

It is a Win32 program, and requires Windows 95 or higher (98, NT, 2000, ME, whatever).

Where to get it

Download this link: (about 60K).
This is version 1.1.1 -- 6 Sep 2001
The C source code is now included in the distribution.

It is free to use and distribute. Please read the license in the file socket45.txt.

Some previous versions are still available:

USE THIS PROGRAM AT YOUR OWN RISK! In order to be useful, Socket45 must execute a plug-in that was written by a third party. This makes it impossible for the author(s) of Socket45 to fully control what may happen when it is used. Since Socket45 does not perfectly emulate a web browser's environment, plug-ins are more likely to malfunction than they are in a web browser. While it is extremely unlikely that anything more serious than a crash will occur, the user of Socket45 must assume full responsibility for that possibility.

Be sure to read the license agreement of any plug-in that you use with Socket45. Some of them forbid their use in a program that is not a web browser (and Socket45 probably qualifies as "not a web browser").

How to install it

Make a directory and extract the file socket45.exe into it.


Changes in version 1.1.1 (6 Sep 2001)

Changes in version 1.1.0 (24 Jun 2001)

My thanks to Paul Chitescu for most of the improvements in this version.

Changes in version 1.0.5 (13 Jan 1999)

Changes in version 1.0.4

There are no functional changes in this version. It was made to keep it in sync with the newly-released source code.

Changes in version 1.0.3

Changes in version 1.0.2

Changes in version 1.0.1

Current status

Most plug-ins that are simply document viewers will work fine. I'd list some plug-ins that are known to work, but it's just too much trouble to maintain such a list.

Network-related and JavaScript-related functions are not implemented. A plug-in that needs to write streams, or read additional streams, or requires LiveConnect, will probably not work. Some plug-ins will work, but with reduced functionality.

Other reasons that a plug-in might not work is that it could very sensitive to quirks in the behavior of the well-known browsers, or that it misbehaves and works outside the plug-in interface (for example, it might search for a running program called "Netscape" and try to communicate with it directly). If a plug-in works with Netscape but not with Internet Explorer, it may not work with Socket45.

If you find an ordinary, freely-available, plug-in that fails to work in Socket45 for no obvious reason, feel free to let me know about it. I can't promise anything, but I might be able to find an easy way to make it work. (Note, I'm not talking about massive, complex plug-ins like Java or RealAudio here....)

What's the point of this, anyway?

So why not just use a browser? Well, in most cases you should just use your browser. Better yet, find a standalone viewer and don't use the plug-in at all. I never said this was a particularly useful program!

But here are some possible uses:

User's Guide

Locate the plug-in you want to use (the file that starts with NP and ends with .DLL), and drag-and-drop it into Socket45. Then locate the data file you want to view and drag-and-drop it into Socket45. You will be asked if you want to use the current plug-in to view that file. Click Yes. The plug-in will now run (hopefully). From the menu, choose File|Save settings by file type. From now on, you can drag-and-drop (or File|Open) data files with the same extension into Socket45, and that plug-in will automatically be loaded and used.


To run a plug-in, Socket45 needs at least 2 pieces of information: The file to view, and the plug-in to use to view it. Press F7 (or File|Setup) to bring up a dialog box that will let you choose this, along with many other bits of information that are usually optional.

Menu commands



You may send comments, suggestions, and constructive criticism via email to Jason Summers at

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