Amazon SQS vs Amazon SNS.

In Simple Words:

• SQS (Queue / Pull Model): Messages sit in a queue until consumer workers pull and process them. Great for decoupling asynchronous background tasks.
• SNS (Pub-Sub / Push Model): Fan-out publisher that pushes a single notification simultaneously to thousands of subscribers (Lambdas, SQS queues, webhooks).

// SNS Fan-out to SQS Queue:
import { SNSClient, PublishCommand } from "@aws-sdk/client-sns";

const sns = new SNSClient({});
await sns.send(new PublishCommand({
  TopicArn: "arn:aws:sns:us-east-1:123456789:NewOrderTopic",
  Message: JSON.stringify({ orderId: "ord_101", total: 49.99 })
}));