SNS

Simple Notification Service — publish-subscribe messaging.

Fully Supported

Full SNS emulation using the AWS Query/XML protocol. Create topics, manage subscriptions, publish messages with fanout to SQS queues and Lambda functions. Supports FIFO topics, message attribute filtering, and subscription filter policies.

Terraform Compatible

Unknown SNS actions return empty success responses, so production .tf files work without modification. Route detection uses Version=2010-03-31.

Supported Operations

Operation	Description	Status
CreateTopic	Create a new SNS topic	Full
DeleteTopic	Delete a topic and all subscriptions	Full
ListTopics	List all topics in the account	Full
GetTopicAttributes	Get topic configuration and metadata	Full
SetTopicAttributes	Update topic attributes	Full
Subscribe	Subscribe an endpoint to a topic	Full
Unsubscribe	Remove a subscription	Full
ListSubscriptions	List all subscriptions	Full
ListSubscriptionsByTopic	List subscriptions for a specific topic	Full
GetSubscriptionAttributes	Get subscription configuration	Full
SetSubscriptionAttributes	Update subscription attributes	Full
Publish	Publish a message to a topic	Full
PublishBatch	Publish up to 10 messages in a single call	Full
TagResource	Add tags to a topic	Full
UntagResource	Remove tags from a topic	Full
ListTagsForResource	List tags on a topic	Full

Stubbed Actions

Actions not listed above (e.g. ConfirmSubscription, AddPermission, RemovePermission) return 200 OK with an empty result. Check server logs for [sns] unhandled action entries.

Subscription Protocols

• SQS — Messages delivered with SNS envelope (or raw via RawMessageDelivery=true)
• Lambda — Asynchronous invocation with SNS event record

Features

• FIFO topics with content-based deduplication
• Message attribute filtering via FilterPolicy
• Filter policy scopes (MessageAttributes or MessageBody)
• Tag management for all topics

Usage

Tarn

# Create a topic
tarn sns create-topic --name events

# Subscribe an SQS queue
tarn sns subscribe \
  --topic-arn arn:aws:sns:us-east-1:000000000000:events \
  --protocol sqs \
  --endpoint arn:aws:sqs:us-east-1:000000000000:worker

# Publish a message
tarn sns publish \
  --topic-arn arn:aws:sns:us-east-1:000000000000:events \
  --message '{"orderId":"12345"}'

AWS CLI

# Create a topic
aws sns create-topic --name events \
  --endpoint-url http://localhost:4566

# Subscribe an SQS queue
aws sns subscribe \
  --topic-arn arn:aws:sns:us-east-1:000000000000:events \
  --protocol sqs \
  --notification-endpoint arn:aws:sqs:us-east-1:000000000000:worker \
  --endpoint-url http://localhost:4566

# Publish a message
aws sns publish \
  --topic-arn arn:aws:sns:us-east-1:000000000000:events \
  --message '{"orderId":"12345"}' \
  --endpoint-url http://localhost:4566

Usage: Terraform

resource "aws_sns_topic" "events" {
  name = "events"
  tags = {
    Environment = "dev"
  }
}

resource "aws_sns_topic_subscription" "worker" {
  topic_arn            = aws_sns_topic.events.arn
  protocol             = "sqs"
  endpoint             = aws_sqs_queue.worker.arn
  raw_message_delivery = true
}

Endpoint

http://localhost:4566

Terraform key

endpoints.sns

See Terraform guide for the full provider configuration.

Usage: AWS SDK

JavaScript

import { SNSClient, CreateTopicCommand, SubscribeCommand, PublishCommand } from "@aws-sdk/client-sns";

const sns = new SNSClient({ endpoint: "http://127.0.0.1:4566" });

// Create topic
const topicRes = await sns.send(new CreateTopicCommand({ Name: "orders" }));

// Subscribe Lambda
await sns.send(new SubscribeCommand({
  TopicArn: topicRes.TopicArn,
  Protocol: "lambda",
  Endpoint: "arn:aws:lambda:us-east-1:000000000000:function:process-order"
}));

// Publish with attributes
await sns.send(new PublishCommand({
  TopicArn: topicRes.TopicArn,
  Message: JSON.stringify({ orderId: "123", total: 99.99 }),
  MessageAttributes: {
    event: { DataType: "String", StringValue: "order-placed" }
  }
}));

Filter Policies

Subscriptions support message attribute filtering. Set a FilterPolicy on the subscription to control which messages are delivered.

{
  "eventType": ["order.created", "order.updated"],
  "priority": [{ "numeric": [">", 0, "<=", 5] }]
}

await sns.send(new SetSubscriptionAttributesCommand({
  SubscriptionArn: "...",
  AttributeName: "FilterPolicy",
  AttributeValue: JSON.stringify(filterPolicy)
}));

Protocol

• Protocol: Query/XML (POST / with Action=...)
• Version: 2010-03-31
• Namespace: http://sns.amazonaws.com/doc/2010-03-31/

Known Limitations

• Subscription protocols limited to SQS and Lambda (no HTTP/S, email, or SMS)
• No cross-account topic/subscription support
• Topic policies (AddPermission / RemovePermission) are stubbed