Amazon SNS vs Google Cloud Pub/Sub

Amazon SNS is a managed publish/subscribe service for sending messages between applications and reaching people. It can deliver notifications to application endpoints and send SMS, mobile push, and email. Standard topics support nearly unlimited messages per second with best-effort ordering and deduplication; FIFO topics preserve order and prevent duplicate delivery within five minutes, with limits of 3,000 messages per second or 10 MB per second per topic. Publishers can batch 1 to 10 messages per request, while subscribers can filter notifications. Integrations include AWS event sources and destinations such as SQS, Data Firehose, Lambda, and HTTPS. Each message can contain up to 256 KB; the Extended Client Library can store payloads up to 2 GB in S3 and publish an object reference. SNS retries delivery and supports dead-letter queues. The free tier includes 1 million requests, 100,000 HTTP notifications, and 1,000 email notifications each month. Listed paid rates include $0.50 per month for API requests, $0.06 for HTTP deliveries, and $2.00 for email deliveries; charges depend on usage.

Google Cloud Pub/Sub is a cloud messaging service for asynchronous communication between services that produce messages and those that process them. It is intended for service-to-service use, including streaming analytics, data integration, middleware, and parallel task queues, rather than direct communication with end users or IoT clients. Communication typically has latency around 100 milliseconds. Synchronous cross-zone replication and per-message receipt tracking provide at-least-once delivery; Dataflow supports exactly-once processing of Pub/Sub streams. There are no shards or partitions, and provisioning scales automatically after quota is set. Message controls include seek and replay, dead letter topics, and attribute-based filtering. Pub/Sub offers fine-grained access controls, end-to-end encryption, and HIPAA compliance. It supports REST and gRPC APIs and client libraries for seven languages; API keys are not supported for authentication. The maximum message size is 10 MB. The free monthly tier is free for the first 10 GB of data per month. Pay-as-you-go is $40 a month beyond 10 GB, with throughput listed at $40 per TB and storage at $0.27 per GiB-month.