> For the complete documentation index, see [llms.txt](https://karansingh.gitbook.io/aws-saa-c02/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://karansingh.gitbook.io/aws-saa-c02/simple-queue-service-sqs/fifo-queues.md).

# FIFO Queues

* FIFO (First-In-First-Out) queues are designed to enhance messaging between applications **when the order of operations and events is critical**, or **where duplicates can't be tolerated**.<br>
* FIFO queues also provide exactly-once processing but **have a limited number of transactions per second (TPS)**.

## Examples

* Ensure that user-entered **commands are executed in the right order**.<br>
* Display the **correct product price by sending price modifications in the right order**.<br>
* **Prevent a student from enrolling in a course before registering for an account**.