如何将Gmail邮箱标签与第三方应用程序集成？

We've a custom CRM application for which we have extensions in IBM Notes & MS Outlook, basically our CRM application can be accessed from Notes & Outlook. In the same way, we would like to extend the application to support through GMail. Basically, our customers would like to see their custom objects/data inside various labels/folders under GMail inbox. As per our understanding, this requires some kind of dynamic pulg-in into the GMail inbox. What is the standard/official way of doing this, please suggest.We've a custom CRM application for which we hav