Raystack Stencil
Raystack Stencil is an open-source schema registry for managing and validating schemas so applications can maintain data compatibility.
What Raystack Stencil is
Raystack Stencil is an open-source schema registry for managing and validating schemas so applications can maintain data compatibility. It supports Protobuf, Avro, and JSON, and stores versioned proto descriptor history by namespace and name. Uploads receive backward-compatibility checks by default, with options to skip some checks. Its APIs can retrieve the latest version number for a schema name and namespace or download contained proto descriptors for a specified message. The server exposes gRPC and HTTP APIs, and a CLI can create, view, and search schemas. Listed clients include Java, Go, JavaScript, and Clojure; they can download descriptor sets, deserialize Protobuf messages, find descriptors, and refresh schema definitions using built-in strategies. The server can run from a Docker image or be compiled from source, with installation options for several operating systems. PostgreSQL 13 is listed as a server requirement. One client limitation: refreshing a descriptor after encountering unknown fields is supported only by the Java and Go clients. Stencil is licensed under Apache-2.0.
Good
- Supports Protobuf, Avro, and JSON schemas
- Stores versioned proto descriptor history
- Checks backward compatibility on uploads by default
- Provides gRPC and HTTP server APIs
- CLI can create, view, and search schemas
Watch out
- Server requires PostgreSQL 13
- Unknown-field-triggered refresh is limited to Java and Go clients
- Ruby and Python clients are listed as coming soon
Who it suits
Stencil suits teams that need a shared registry for schema definitions across producers, consumers, and developers. It is relevant for systems using Protobuf, Avro, or JSON, particularly when compatibility checks and version history matter.
Verdict
Stencil combines schema versioning, compatibility checks, APIs, and client libraries for supported formats. Account for its PostgreSQL requirement and client-specific refresh limitation when considering deployment.
The facts
Each one read from Raystack Stencil's own pages, with the date it was checked.
What it does
- CLI
- The CLI can create, view, and search schemas through the server.checked 5 Oct 2026
- Client features
- Clients can download descriptor set files, deserialize Protobuf encoded messages, look up proto descriptors, and refresh schema definitions using built-in strategies.checked 4 Oct 2026
- Client languages
- Official clients are supported for Java, Go, and JavaScript, with Clojure also listed among the client languages.checked 4 Oct 2026
- Client libraries
- The repository lists Java, Go, JavaScript, and Clojure clients, with Ruby and Python marked as coming soon.checked 5 Oct 2026
- Client refresh limitation
- Refreshing a descriptor file only when a client encounters unknown fields is currently supported by the Java and Go clients.checked 4 Oct 2026
- Compatibility
- Stencil enforces backward compatibility checks on upload by default and allows some checks to be skipped.checked 4 Oct 2026
- Compatibility checks
- Uploads are checked for backward compatibility by default, with an option to skip some checks.checked 5 Oct 2026
- Deployment
- Stencil can be run as a server and is distributed as cross-platform binaries and Docker images.checked 5 Oct 2026
- Descriptor downloads
- Users can download proto descriptor files from Stencil.checked 5 Oct 2026
- Intended users
- The project describes its users as developers who create, manage, and consume schemas across applications.checked 5 Oct 2026
- License
- The repository is published under the Apache-2.0 license.checked 5 Oct 2026
- Metadata API
- A metadata API retrieves the latest version number for a given name and namespace.checked 5 Oct 2026
- Purpose
- Stencil is a schema registry for managing and validating schemas to maintain data compatibility across applications.checked 5 Oct 2026
- Schema formats
- It supports Protobuf, Avro, and JSON schemas.checked 5 Oct 2026
- Server APIs
- The server provides gRPC and HTTP APIs for interacting with Stencil.checked 5 Oct 2026
- Server interfaces
- The server provides REST access for storing and retrieving Protobuf file descriptors and the repository README also describes gRPC and HTTP APIs.checked 4 Oct 2026
- Server requirement
- The server documentation lists PostgreSQL 13 as a requirement.checked 4 Oct 2026
- Supported formats
- Stencil supports Protobuf, Avro, and JSON formats.checked 4 Oct 2026
- Version history
- Stencil stores versioned history of proto descriptor files by namespace and name.checked 5 Oct 2026
Where it runs
- Installation platforms
- The README lists macOS, Windows, Linux, OpenBSD, and FreeBSD installation options.checked 5 Oct 2026
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