Simple Queue Service (SQS)
- Pull-based queue used to decouple infrastructure
- 256 KB message size limit, buy can use Java SDK to send larger payloads to S3
- Retention period from one min to 14 days, defaults to four days
- Visibility timeout is time message is invisible once read, limit of 12 hours
- Long polling can reduce costs by not returning until a message arrives or timeout is reached
- Types
- Standard: no ordering guarantees, at-least-once delivery
- FIFO: strong ordering, exactly-once delivery
