I'm trying out to figure out whether a user has the permission to play a track, before attempting to send a call to the player endpoint.
The field "product" is useless in its current state, as there is no documentations about all the product types that can be returned, and what are the specificity of the product types in general.
Here is its vague description: The user’s Spotify subscription level: “premium”, “free”, etc. (The subscription level “open” can be considered the same as “free”.).
I personally remember seeing a subscription level for the free trial, where I had access to the player endpoint.