In general, when asking about interfacing one product (in this case, Notepad++) with some other external product (in this case, SimpleNote), it’s considered polite to provide links to and/or descriptions of what SimpleNote is – I had to do a web search to find out what it is.

As far as I know, there is no Notepad++ plugin to deal with SimpleNote – definitely not in the Plugins Admin plugin list. There may be one somewhere, but I don’t know what it is.

After a brief search on SimpleNote, I saw that it has both a web interface and a local Windows app. Are you looking to connect to the web data, or to the data for a local app version? I think I saw that it’s default filetype is JSON – Notepad++ can read the raw JSON, but it won’t interpret it the way that SimpleNote does – but maybe opening the SimpleNote .json file with Notepad++ and using the JSON Viewer plugin would give you something like what you want.

I guess the real question is “what are you trying to accomplish?” Because that might affect what answers people give.