I have gone through the developer site:
In the authentication API, one the input is client_id
client_id string Indicates the client that is making the request. The value passed in this parameter must exactly match the value set during the partnership program.
But, I do not see where can I get the client_id nor anything about the partnership program.
The page says:
Once you sign-up for Feedly Cloud Developer Program, you will receive a client id and client secret you can use to authenticate to the sandbox.
I assume they will send you the id via email?