Google Cloud Pub/Sub vs IronMQ

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.

IronMQ is a persistent message queue for communication between services and components in distributed applications. It supports push and pull queues, long polling, error queues, alerts, and triggers, as well as dead-letter queues and ordering within each queue. Delivery is described as best-effort and one-time, a behavior application teams should account for in message handling. Its HTTPS and REST-based APIs support HTTP/REST, Amazon SQS, and OpenStack Marconi protocols. During an outage, queues can automatically point to alternative availability zones without code changes. Deployment options include shared, dedicated, and on-premise environments. Documentation lists client libraries for Go, Ruby,.NET, Java, PHP, Python, Node, and Rust, plus community-supported Apache Camel and Clojure libraries. Iron.io says OAuth and SSL protect data in transit, and recommends client-side encryption for especially sensitive payloads at rest. The free Basic plan includes 100K API requests per month, limited queues, and a 64k message size limit. Entry costs $399 a month; a full-feature 14-day trial is offered for non-dedicated clusters.