As one piece of feedback, the docs could be better. For example, at https://docs.tryvital.io/api-reference/data/workouts/#stream, I see "Get Daily Activity for user_id", but the endpoint seems to actually return time series data for a single workout. I see a bunch of oversights of this flavor.
Similarly, I'm not sure how pagination works or should work. In one list query, I see a result set of size 100. I'm not sure whether this is because only 100 items were pulled from the provider, or whether I can see more using pagination. Maybe this is in the docs, but I haven't seen it.
It would be good to have some provider-specific documentation to answer questions are set expectations around things like 1) how much historical data is available 2) details about the integration and its stability. For example, I assume with Peloton you are logging in with my credentials and using their internal API. Is this against their terms of service? Is there a risk of this breaking if they change their internal API, which obviously doesn't have the same governance considerations a public API would?
Nice work overall!