Question on client authentication

https://api.producthunt.com/v2/d... Have some questions for client level authentication. 1. How long does the token from oauth#token valid, is there an expiration? 2. Not sure about the flow, so with this client authen - when an app launch I make post request to /v2/oauth/token - save the token - use this token for others requests or - I just make post request to /v2/oauth/token on my machine and hard code this into app?