Buf Schema Registry vs Raystack Stencil

Buf Schema Registry (BSR) is a Protobuf-aware registry for managing API schemas, dependencies, and client access as APIs change. Teams publish Protobuf files as versioned modules and resolve dependencies declared in buf.yaml. BSR generates hosted SDKs for supported languages and browsable documentation from schema versions and comments. Server-side lint and breaking-change policies can reject updates or hold them for review. The registry also shows which modules depend on another, helping teams identify affected consumers before deprecation. A GitHub Action handles build, lint, formatting, breaking-change checks, and publishing; the Buf CLI can connect to other CI/CD systems. RPC APIs are available through Connect, gRPC, and gRPC-Web. Community costs nothing and includes one private repository limited to 100 types plus unlimited public repositories. Teams costs $0.50 a month per type and includes a 30-day trial. Pro costs $5 a month per type with a $3000/month minimum spend. Enterprise pricing is custom.

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.