Gmail API Push notifications: don't call us, we'll call you
If your app needs to keep up with changes in a Gmail mailbox, whether it's new mail being received or a label being added, you are likely familiar with periodically polling the Gmail API's history feed for updates. If you find this tedious, we have good news for you. Today, at Google I/O 2015, we're launching push notifications for the Gmail API.
Just subscribe to a Gmail mailbox and whenever a change occurs, the Gmail API will instantly notify your server using webhooks or another Cloud Pub/Sub API notification method. No polling required.
Check out the developers’ guide at https://developers.google.com/gmail/api/guides/push to get started. We can’t wait to see what you build.