You could look into using the
Google Analytics Super proxy. The Google Analytics superProxy allows you to publicly share your Google Analytics reporting data. You can use it to power your own custom dashboards and widgets, transform responses to various formats, test, and much more.
Or you could look into using an
authenticated service account. The Google OAuth 2.0 system supports server-to-server interactions such as those between a web application and a Google service. For this scenario you need a service account, which is an account that belongs to your application instead of to an individual end user. Your application calls Google APIs on behalf of the service account, so users aren't directly involved.
-Matt