Amazon SNS
Amazon Simple Notification Service (Amazon SNS) is a serverless publish/subscribe notification service from Amazon Web Services that delivers messages from publishers to subscribers, sending both text and email messages from distributed applications.
Key points
- Creates asynchronous communication between publishers and subscribers by sending messages to a topic.
- Supports application-to-application subscribers, including Amazon SQS and other AWS services, and application-to-person subscribers, including mobile SMS and email.
- The producer sends one message to one SNS topic; multiple receivers (subscribers) listen for the notification, and all subscribers receive all messages.
- Example: 1 message sent to 1 topic with 10 subscribers notifies 10 different subscribers.
- Publishes messages to many subscriber endpoints: Amazon SQS queues, AWS Lambda functions, email, Amazon Kinesis Data Firehose, mobile push, and SMS.
- Can be used to send both text and email messages from distributed applications, such as an SNS alert when EC2 CPU exceeds 80% for 5 minutes.
- FIFO topics add strict message ordering and deduplication (5-minute dedup window) on top of standard SNS, for workflows like bank transaction logging or inventory updates; they support up to 3,000 messages per second (or 10 MB/s) per topic, and can only deliver to Amazon SQS FIFO queues as subscribers.
- Message filtering lets each subscriber attach a filter policy so it only receives the subset of a topic’s messages it cares about (matching on message attributes or body), instead of every subscriber getting every message — this moves filtering logic out of the subscriber application and onto the topic itself.
- Message data protection could inspect outbound messages for sensitive data patterns (PII/PHI) and de-identify them via masking or redaction before delivery, in addition to SNS’s standard in-transit/at-rest encryption via AWS Key Management Service (KMS). AWS closed this feature to new customers on April 30, 2026 — existing configured policies keep working, but AWS now points new customers to a Lambda + Amazon Bedrock Guardrails architecture instead for real-time sensitive-data detection.
- Distinct from Amazon SQS: SNS immediately pushes each message to every subscriber (fan-out, no storage), while SQS holds messages in a queue for one or more consumers to pull and process at their own pace.