Aiven for Apache Kafka vs Google Cloud Pub/Sub

Aiven for Apache Kafka is a managed Kafka service that handles provisioning, patching, backups, security, and high availability. It runs on AWS, Google Cloud, Azure, DigitalOcean, OVH, and UpCloud, with cloud availability varying by plan. Tiered storage and diskless topics can keep topic data in cloud object storage so storage and compute scale independently. A managed Schema Registry powered by the open-source Karapace project is included, alongside predictive consumer-lag monitoring, Kafka Connect compatibility, and a REST proxy. Aiven describes clusters with automatic node recovery and multi-node deployment across availability zones, and lists a 99.99% uptime SLA for Professional. Connections can use mTLS and/or SASL authentication with ACL authorization; stored data is encrypted. The Free plan costs nothing and is capped at 250 KiB/s throughput, three days of retention, and five topics with two partitions each. Developer costs $35 a month, while Professional costs $180 a month. A free 30-day trial is listed for more memory or advanced features.

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.