I'm working on a website which has the api (Ruby on Rails) and the client (Angular JS) on separated servers.
As of that, I authenticate the user on the client with LinkedIn, I post the received data to the API's authentication method and I get JWT back from it.
Then I authenticate with the token attached to every request, while making all the LinkedIn API requests on the backend.
I see there were a lot of posts about how to exchange jsapi token to oauth token, but they have all been removed from LinkedIn's page and there are no usable information in the stored data.
Note: all other StackOverflow answers are linking to those pages too.