Amazon SNS vs Faye

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.

Faye is a publish-subscribe messaging system that uses the Bayeux protocol. It provides message servers for Node.js and Ruby, plus clients for servers and major web browsers. Browser clients rely on a Faye server to relay messages; they can retry after a lost connection and redeliver dropped messages. Transport adapters cover WebSocket, HTTP long-polling, Cross Origin Resource Sharing, and JSON-P callback-polling. Server and client extensions can intercept or modify messages, including to add subscription authentication. The monitoring API reports handshakes, subscriptions, unsubscriptions, publishes, and disconnections. Faye runs on Linux, macOS, and Windows, and can be self-hosted. Its default in-process engine cannot span multiple front-end web servers, but Redis and Couchbase engines are documented for distributed deployments. Faye is free and open source under the Apache 2.0 license; the listed plan is free. Install the Node.js server through npm or the Ruby server through RubyGems.