I made a chat application (run on my own website) built for streamer but I’m looking for a way to transform my application to extension because I have some issue to promote its. I want to register its on: https://www.twitch.tv/username/dashboard/extensions.
A chat application wouldn’t really make sense as an extension. Extensions can be a video overlay, a component, a panel, or mobile, all of which would be somewhat redundant for your use case as Twitch is already displaying chat so why would a streamer want to duplicate that in a panel or over their stream?
You’re right in that extensions are aimed at end users. If you want to do something to enhance chat functionality on Twitch then perhaps consider doing what FFZ or BTTV do and use a browser extension to add features to chat.
Like you said the actual chat is “aimed at end users”. I made my chat application to show more messages than the usual chat.
Before to be an application & website my chat was a userscript (like browser extension) on Twitch website, but my chat got better performence (cpu & ram usage) without this integration on Twitch website.