messaging

On 18 Sep 2026 SNS raised the payload ceiling to 1 MiB, four times 256 KiB, but only after you set MaximumMessageSize. A full 1 MiB Standard publish is 16 requests. At 50 cents per million requests, one million of those publishes cost 8 dollars before the free tier.

Amazon MQ bills per broker instance hour — an mq.m5.large active/standby HA pair is ~$440/month before storage. Add EFS or EBS for the broker, and a typical production HA deployment lands at $700+/month with zero messages flowing. Use MQ only when AMQP, JMS, STOMP, MQTT, or OpenWire protocol compatibility is non-negotiable.

SNS bills publish and delivery separately. Standard topic publish is $0.50/M, but HTTP delivery is $0.60/M on top, email is $2/100K, SMS varies by country, and mobile push is $0.50/M. A single publish to a topic fanned out to four protocols generates four billable lines — five if you count the cross-region data transfer.

SQS charges $0.40 per million standard requests and $0.50 per million FIFO requests, but a single 256 KB message counts as four requests under the 64 KB rule. Short polling on idle queues silently quadruples the bill. Cross-region data transfer adds a line many teams never count.

Consumer group rebalance storms stall processing longer than broker outages. This guide covers cooperative rebalancing, idempotent producers, and transactional reads on Amazon MSK—with when SQS FIFO is simpler.

FIFO guarantees shrink throughput—and unbounded queues only move backpressure to your AWS bill. Ordering, flow control, and Amazon MQ dead-letter patterns vs Kinesis resharding.

SQS is "reliable" only if you understand visibility timeout, dead-letter queues, and the silent failure mode where messages get processed twice. Standard vs FIFO, DLQ tuning, Lambda integration, and the patterns that turn SQS from "queue with default settings" into reliable backbone messaging.