The main difference between SQS and SNS is that SQS is a message queue while SNS is a notification service. With SQS, you can store messages in a queue and then process them at your leisure. This is useful if you have a process that can take some time and you don’t want to tie up your main application while it is running. SNS, on the other hand, is designed to send notifications immediately. This can be useful for things like sending text messages or emails in response to events.