Amazon SQS
Decoupling applications with Standard vs FIFO Queues
Standard Queues
The default queue type. Offers maximum throughput and best-effort ordering.
- Unlimited Throughput: Nearly infinite transactions per second.
- At-Least-Once: Message delivered at least once (duplicates possible).
- Best-Effort Ordering: Messages usually arrive in order sent.
FIFO Queues
First-In-First-Out. Designed for applications where order and uniqueness are critical.
- High Throughput: Up to 3,000 messages/sec (with batching).
- Exactly-Once: No duplicates; messages processed exactly once.
- Strict Ordering: First message in is the first message out.
The Delivery Logic
STANDARD: “Jumbled Delivery”
Messages may arrive out of order or more than once.
FIFO: “Strict Sequence”
Messages are processed exactly once, in the order they were sent.