Can I know in which point we need to validate the JWT expiration?

Question

I am quite new to JWT based authentication. And im quite confused about the refresh token mechanism. In my case, I have designed my application as,
1. User will login to the application, and when the login is successful then it will go to the authentication server and sign a jwt and will pass it to the client.
2. And then the client will store the refresh token and the short lived token in the local storage
3. Once the resource server is called the token will be sent through the header. and will get validated.

My question is, in which point should we request another token using the refresh token mechanism. Should we check whether the short lived token is invlaid before sending the request to the resource server. or should we get a new token once the validation fails in resource server? or is there any better way to handle this?

Answer 1

A Refresh Token is a special kind of token that can be used to obtain a renewed access token —that allows accessing a protected resource— at any time.

Although Access Tokens can be renewed at any time using Refresh Tokens, they should be renewed when old ones have expired, or when getting access to a new resource for the first time. Refresh Tokens never expire OR have very long expiration time.