Apicurio Registry vs Google Cloud Pub/Sub

Apicurio Registry is an open-source runtime server for storing API designs and schemas as artifacts. Users can add, update, and remove artifacts through a remote REST API. For API discovery, teams can register designs such as OpenAPI, AsyncAPI, and GraphQL so consumers can search and browse APIs, see details, and read generated documentation. For messaging and event streaming, it provides a central place to track schemas and manage data-format evolution. Supported artifact types include OpenAPI, AsyncAPI, GraphQL, Apache Avro, Protocol Buffers, JSON Schema, Kafka Connect schema, WSDL, XML Schema, and ODCS v3.1. Configurable rules can check validity, compatibility, and integrity as artifacts change. Listed storage backends include Apache Kafka, PostgreSQL, and Microsoft SQL Server. Management options include a web console, REST API, command line, Maven plug-in, and Java client. Kafka serializers and deserializers can enforce schemas in producer and consumer applications. The documentation covers self-hosted deployment, including Kubernetes. The quick-start in-memory server is non-persistent and is not intended for production.

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.