Normally, in direct integration, a service sends one message to many receivers.
In pub/sub system (publish/subscribe), a service publishes into SNS topic, which has multiple subscribers

In SNS:
- The ‘event producer’ only sends message to one SNS topic
- You can have as many ‘event receivers’ as you want to list SNS topic notifications
- Each subscriber will get all messages (filtering also available)
- Up to 12.000.000 subscription per topic and 100.000 topic limit
How to Publish
Topic Publish (using SDK)
- Create a topic
- Create a subscription (or many)
- Publish the topic
Direct Publish (for mobile apps SDK)
- Create a platform application
- Create a platform endpoint
- Publish to platform endpoint
- Works with Google GCM, Apple APNS, Amazon ADM
Subscription Services
- Amazon Kinesis Data Firehose
- Amazon SQS
- AWS Lambda
- Email-JSON
- HTTP
- HTTPS
- Platform application endpoint
- SMS