<p>I'm looking for a open source .Net HTTP proxy library. Basically I want to develop something like Fiddler (so much lighter with less features).</p>

There is
URLRewriter.NET
, a free open-source component for IIS/ASP.NET.
As the name suggests, it's an URL rewriting component, but it has
also proxying capabilities
. With a simple line like this in the configuration file
```
```
RewriteRule ^(.*) http://www.testsiteXY.com$1 [P]
```
```
you could easily use it as proxy.