Apache Pulsar vs Raystack Stencil

Apache Pulsar is a free, open-source distributed messaging and streaming platform built for cloud use. It supports message consumption with less than 10 ms latency and up to one million unique topics in a cluster. Configurable replication across geographic regions and automatic client failover to healthy clusters support multi-region deployments. Tenants and policies control access to data and actions, and can isolate brokers to limit noisy-neighbor effects. Maintained client libraries are available for Java, Go, Python, C++, Node.js, and C#. Built-in connectors move data to and from systems including Kafka, RabbitMQ, MySQL, PostgreSQL, MongoDB, Cassandra, and Elasticsearch. Pulsar Functions process messages with user-defined logic in Java, Python, or Go. Tiered storage can offload data from BookKeeper to blob storage such as S3 for unlimited retention. It can run in Docker or Kubernetes, with a Helm chart for Kubernetes. Encryption, authentication, and authorization are available but are not enabled by default. The 5.0.0-M2 milestone is for early testing and feedback, not production use.

Raystack Stencil is a schema registry for managing schema definitions and checking data compatibility across applications. It supports Protobuf, Avro, and JSON, and keeps versioned histories of proto descriptor files organized by namespace and name. Uploads receive backward-compatibility checks by default, though some checks can be skipped. The service provides APIs for retrieving the latest version number for a schema name and namespace and downloading the proto descriptors contained in a specified message. Its server offers gRPC and HTTP interfaces, while a CLI can create, view, and search schemas. Listed client libraries cover Java, Go, JavaScript, and Clojure. Clients can download descriptor sets, deserialize Protobuf messages, look up descriptors, and refresh schema definitions with built-in strategies. Stencil can run from a Docker image or be compiled from source, with installation options for macOS, Windows, Linux, OpenBSD, and FreeBSD. The server requires PostgreSQL 13. Refreshing a descriptor after encountering unknown fields is supported only by the Java and Go clients. The project is open source under Apache-2.0.