- Messages can contain up to 256kb of text in any format.
- Standard Queue more than one copy of a message might be delivered out of order.
- FIFO queue ensure ::ordering:: and a message is delivered ::once:: only.
- SQS is ::pull based::.
- Messages can be kept from 1 min to 14 days, default is 4 days.
- SQS guarantees messages will be processed at least once.
- SQS visibility timeout: default is 30 sec, up to 12 hours.
- Short polling vs Long polling