This tutorial will be tell how to use Okhttp Authenticator with Retrofit. This authenticator method is usefull when we having a case like : Re-authorization without a user interaction (login) Requesting new API access token with refresh token This tutorial will cover the second case ( access token dan refresh token ) which is commonly use. The case will have scenario like this : Normal API request. When token or API key expired, API will return 401. Okhttp Authenticator will intercept the process. Okhttp Authenticator will requesting new token with refresh token. New token receive and API request will be reloaded automatically. So, first create ApiAdapter class which is a class that contain retrofit singleton. In this class add method getAdapter(). public class ApiClient { public static Retrofit getAdapter() { if (retrofit==null) { final OkHttpClient.Builder httpClient = new OkHttpClient.Builder(); httpClient.addInterceptor(new Intercepto