aws-sns

---

title: "Aws Sns" sidebar_label: "Aws Sns" description: "AWS SNS notification service for pub/sub messaging. Use when creating topics, managing subscriptions, configuring message filtering, sending notifications, or setting up fan-out patterns."

Aws Sns

AWS SNS notification service for pub/sub messaging. Use when creating topics, managing subscriptions, configuring message filtering, sending notifications, or setting up fan-out patterns.

Details

Property	Value
Skill Directory	.github/skills/aws-sns/
Phase	General
User Invocable	✅ Yes
Usage	/aws-sns Topic type, subscription protocol, or pattern to look up (e.g. 'FIFO topic', 'Lambda subscription', 'message filter policy', 'fan-out to SQS')

Documentation

AWS SNS

Amazon Simple Notification Service (SNS) is a fully managed pub/sub messaging service for application-to-application (A2A) and application-to-person (A2P) communication.

Table of Contents

• Core Concepts
• Common Patterns
• CLI Reference
• Best Practices
• Troubleshooting
• References

Core Concepts

Topics

Named channels for publishing messages. Publishers send to topics, subscribers receive from topics.

Topic Types

Type	Description	Use Case
Standard	Best-effort ordering, at-least-once	Most use cases
FIFO	Strict ordering, exactly-once	Order-sensitive

Subscription Protocols

Protocol	Description
Lambda	Invoke Lambda function
SQS	Send to SQS queue
HTTP/HTTPS	POST to endpoint
Email	Send email
SMS	Send text message
Application	Mobile push notification

Message Filtering

Route messages to specific subscribers based on message attributes.

Common Patterns

Create Topic and Subscribe

AWS CLI:

# Create standard topic
aws sns create-topic --name my-topic

# Create FIFO topic
aws sns create-topic \
  --name my-topic.fifo \
  --attributes FifoTopic=true

# Subscribe Lambda
aws sns subscribe \
  --topic-arn arn:aws:sns:us-east-1:123456789012:my-topic \
  --protocol lambda \
  --notification-endpoint arn:aws:lambda:us-east-1:123456789012:function:my-function

# Subscribe SQS
aws sns subscribe \
  --topic-arn arn:aws:sns:us-east-1:123456789012:my-topic \
  --protocol sqs \
  --notification-endpoint arn:aws:sqs:us-east-1:123456789012:my-queue

# Subscribe email
aws sns subscribe \
  --topic-arn arn:aws:sns:us-east-1:123456789012:my-topic \
  --protocol email \
  --notification-endpoint user@example.com

boto3:

import boto3

sns = boto3.client('sns')

# Create topic
response = sns.create_topic(Name='my-topic')
topic_arn = response['TopicArn']

# Subscribe Lambda
sns.subscribe(
    TopicArn=topic_arn,
    Protocol='lambda',
    Endpoint='arn:aws:lambda:us-east-1:123456789012:function:my-function'
)

# Subscribe SQS with filter
sns.subscribe(
    TopicArn=topic_arn,
    Protocol='sqs',
    Endpoint='arn:aws:sqs:us-east-1:123456789012:order-queue',
    Attributes={
        'FilterPolicy': '{"event_type": ["order_created", "order_updated"]}'
    }
)

Publish Messages

import boto3
import json

sns = boto3.client('sns')
topic_arn = 'arn:aws:sns:us-east-1:123456789012:my-topic'

# Simple publish
sns.publish(
    TopicArn=topic_arn,
    Message='Hello, World!',
    Subject='Notification'
)

# Publish with attributes (for filtering)
sns.publish(
    TopicArn=topic_arn,
    Message=json.dumps({'order_id': '12345', 'status': 'created'}),
    MessageAttributes={
        'event_type': {
            'DataType': 'String',
            'StringValue': 'order_created'
        },
        'priority': {
            'DataType': 'Number',
            'StringValue': '1'
        }
    }
)

Message Filtering

# Add filter policy to subscription
aws sns set-subscription-attributes \
  --subscription-arn arn:aws:sns:us-east-1:123456789012:my-topic:abc123 \
  --attribute-name FilterPolicy \
  --attribute-value '{
    "event_type": ["order_created"],
    "priority": [{"numeric": [">=", 1]}]
  }'

Filter policy examples:

// Exact match
{"event_type": ["order_created", "order_updated"]}

// Prefix match
{"customer_id": [{"prefix": "PREMIUM-"}]}

// Numeric comparison
{"price": [{"numeric": [">=", 100, "<=", 500]}]}

// Exists check
{"customer_id": [{"exists": true}]}

// Anything but
{"event_type": [{"anything-but": ["deleted"]}]}

Fan-Out Pattern (SNS to Multiple SQS)

import boto3
import json

sns = boto3.client('sns')
sqs = boto3.client('sqs')

# Create topic
topic = sns.create_topic(Name='orders-topic')
topic_arn = topic['TopicArn']

# Create queues for different processors
queues = {
    'analytics': sqs.create_queue(QueueName='order-analytics')['QueueUrl'],
    'fulfillment': sqs.create_queue(QueueName='order-fulfillment')['QueueUrl'],
    'notification': sqs.create_queue(QueueName='order-notification')['QueueUrl']
}

# Subscribe each queue
for name, queue_url in queues.items():
    queue_arn = sqs.get_queue_attributes(
        QueueUrl=queue_url,
        AttributeNames=['QueueArn']
    )['Attributes']['QueueArn']

    sns.subscribe(
        TopicArn=topic_arn,
        Protocol='sqs',
        Endpoint=queue_arn
    )

# One publish reaches all queues
sns.publish(
    TopicArn=topic_arn,
    Message=json.dumps({'order_id': '12345', 'total': 99.99})
)

Lambda Permission for SNS

aws lambda add-permission \
  --function-name my-function \
  --statement-id sns-trigger \
  --action lambda:InvokeFunction \
  --principal sns.amazonaws.com \
  --source-arn arn:aws:sns:us-east-1:123456789012:my-topic

CLI Reference

Topic Management

Command	Description
aws sns create-topic	Create topic
aws sns delete-topic	Delete topic
aws sns list-topics	List topics
aws sns get-topic-attributes	Get topic settings
aws sns set-topic-attributes	Update topic settings

Subscriptions

Command	Description
aws sns subscribe	Create subscription
aws sns unsubscribe	Remove subscription
aws sns list-subscriptions	List all subscriptions
aws sns list-subscriptions-by-topic	List topic subscriptions
aws sns confirm-subscription	Confirm pending subscription

Publishing

Command	Description
aws sns publish	Publish message

Best Practices

Reliability

• Use SQS for durability — SNS is push-based, SQS queues messages
• Configure DLQ for failed deliveries
• Use FIFO topics for ordering requirements

Security

• Use topic policies to control access
• Enable encryption with SSE

# Enable SSE
aws sns set-topic-attributes \
  --topic-arn arn:aws:sns:us-east-1:123456789012:my-topic \
  --attribute-name KmsMasterKeyId \
  --attribute-value alias/my-key

Cost Optimization

• Use message filtering to reduce unnecessary deliveries
• Monitor and clean up unused topics/subscriptions

Troubleshooting

Subscription Not Receiving Messages

Check:

1. Subscription is confirmed (not pending)
2. Filter policy matches message attributes
3. Target permissions (Lambda, SQS)

# Check subscription status
aws sns list-subscriptions-by-topic \
  --topic-arn arn:aws:sns:us-east-1:123456789012:my-topic

Messages Not Matching Filter

Verify:

• Message attributes are set (not in body)
• Attribute types match (String vs Number)
• Filter policy syntax is correct

# Correct: attributes must be message attributes
sns.publish(
    TopicArn=topic_arn,
    Message='body content',
    MessageAttributes={
        'event_type': {
            'DataType': 'String',
            'StringValue': 'order_created'  # This is filtered
        }
    }
)

# Wrong: body content is NOT filtered
sns.publish(
    TopicArn=topic_arn,
    Message=json.dumps({'event_type': 'order_created'})
)

SQS Not Receiving from SNS

Check SQS queue policy:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Principal": {"Service": "sns.amazonaws.com"},
      "Action": "sqs:SendMessage",
      "Resource": "arn:aws:sqs:us-east-1:123456789012:my-queue",
      "Condition": {
        "ArnEquals": {
          "aws:SourceArn": "arn:aws:sns:us-east-1:123456789012:my-topic"
        }
      }
    }
  ]
}

References

• SNS Developer Guide
• SNS API Reference
• SNS CLI Reference
• boto3 SNS