Amazon Simple Queue Service

A queue service that safely buffers messages waiting to be processed.

A message queue service. Separates producers from consumers to stabilize asynchronous processing.

• Asynchronous order processing
• Distributing work to Lambda
• Retry buffering during failures

• Provides loose coupling through queues
• Standard Queue and FIFO Queue are available
• Understand the visibility timeout

• Use a Dead Letter Queue to capture failed messages
• Consider FIFO when ordering is required
• Can be used as a Lambda trigger

Amazon SQS is a fully managed message queue service from AWS. By separating the side that sends messages to the queue (the producer) from the side that receives them (the consumer), it asynchronizes processing and loosely couples the system as a whole. Senders can dispatch messages without being aware of consumer availability, and receivers can retrieve and process messages at their own pace, providing a buffer against sudden load spikes. SQS offers two queue types: Standard Queue and FIFO Queue. Standard provides at-least-once delivery without strict ordering, while FIFO provides exactly-once processing with ordering guarantees. In practice, SQS is used for asynchronous order processing, distributing work to Lambda, buffering retries during failures, and passing jobs between ECS tasks. The visibility timeout is an important concept in SQS: it is the period during which a message becomes invisible to other consumers after one consumer has retrieved it but before processing has completed (and the message has been deleted). If processing does not complete within the timeout, the message becomes visible again and can be retrieved by another consumer. This guarantees at-least-once processing, but it requires consumers to ensure idempotency. Pricing is based on the number of API requests, with data transfer volume billed separately. Configuring a dead-letter queue (DLQ) allows messages that fail processing beyond a specified number of attempts to be moved to a separate queue for later investigation. In CLF-C02, the basic concept of SQS as a means of loose coupling through message queues, the distinction between Standard and FIFO, and the visibility timeout are frequent topics.

• What is Amazon Simple Queue Service (AWS Official Documentation)
• Amazon SQS (AWS Official)

Last updated: 2026-06-01