I plan to develop an app for Amazon Selling Partner API (SP-API). The general idea of the app is that it will be the app, that different sellers can use to help them manage their stock on Amazon. I myself am not a seller on Amazon, and I don't work for a particular seller. The app, once ready, should be available to multiple sellers who are interested in using it.
Unfortunatelly from what I found in SP-API documentation here and here it seems it's impossible to register as a developer, without being a seller yourself or having an existing seller that can register you as a developer. Is this correct? If yes, is there any way to overcome this issue? It seems a bit ridiculous that Amazon doesn't provide an easy way for third party developers to develop and test their apps on Amazon.