Google Cloud Pub/Sub is designed to provide reliable, many-to-many, asynchronous messaging between applications. Publisher applications can send messages to a “topic” and other applications can subscribe to that topic to receive the messages. By decoupling senders and receivers, Google Cloud Pub/Sub allows developers to communicate between independently written applications.
For the Beta release, the following limitations apply:
- Applications can only send and receive messages to each other if their Cloud projects belong to the same owner.
- Push messages can only be delivered to HTTPS endpoints. A subscriber application must include a web service component to receive messages, such as a Google App Engine app, or a web server hosted on Google Compute Engine or an external location.
In addition, see Quotas for quota limits.