I'm reasonably confident that the protocol I was working with was json over websocket https://openwebtorrent.com/ tracker this was a few months ago now so peertube could be running something different So each peertube instance runs its own openwebtorrent compatible tracker, which then has its own protocol inforced at the wire level, compared to when i looked at the other openwebtorrent implementations depending on the server didn't enforce the wire format and you could send json over the wire, the trackers seemed to just be a sort of pubsub system where announces would get resent to other connected clients under the same infohash or whatever they used