We have now discussed the basic flow of how refresh tokens work, as well as implementing a means of performing that flow by adding an additional API endpoint to our server. All that remains is deciding how we actually modify the frontend of the application to automatically handle our refresh token flow without letting the user know what's happening.

We know that we need to watch every API call for a 401 HTTP status code response and attempt to obtain a new access token by hitting the refresh token API endpoint. We also know that we don't want to be doing this manually on every API request in the system, as it would be completely impractical to try and maintain them if the logic ever changed. We need a way of defining this logic in a single place and have it automatically work any time we add new API requests in the future...