UPDATE2 : For some reason, Blogger lost the original post. I had to republish it. UPDATE : Jerónimo told me that you must use the Npgsql version which is inside the zip file in order to make it work. After so much time (more than I wanted it to take) Npgsql finally has a initial design time support for Visual Studio! This work was done by Jerónimo Milea. Jerónimo let me know he was working on DDEX support on this thread after I said I was working on DDEX support for Npgsql. He sent me his working copy and I started to play with it. Note that as a preview version many things may not work ok and we wanted you to provide us feedback so we can fix any bugs. You can download the project file from our downloads page . Design time support is provided as a zip file containing support code as well as a copy of Npgsql project file. So, everything you need to start working with design time support is already packaged for you. When you unzip the file, you will have three folders