The last couple of days I have been wondering in the magic world of Identity Federation. Although the windows identity foundation SDK provides a great tool to associate an RP (Relying Party) application with an existing STS (Security Token Service), it requires that the STS have a Federation metadata xml file. If you simply want to automatically generate the STS from the application, then the SDK provide the automatic STS generation on the right click of the RP website, which generates a new STS web site (in c#) based on the RP’s web config file. On the other hand, if you are up to creating a new custom STS without the RP, then you have to manually create the manifest file, which is really very frustrating! On my search around the net I found a couple of federation metadata file creators but none of them had the ability to edit an existing one. Unfortunately, I had to edit the manifest file quite often and thus I had to create a tool to do so. This is why I created the STS Federation Metadata Editor which you may download freely on the following link.Hope this simplifies your custom STS development efforts!