class AuthenticateInterceptor() : Interceptor { override fun intercept(chain: Interceptor.Chain): Response { var request = chain.request() request.let { val builder = it.newBuilder() val credentials = Credentials.basic("client_id", "client_secret") builder.addHeader("Authorization", credentials) request = builder.build() } return chain.proceed(request) } } Retrofit.Builder() .client(getOkHttpCli..