README.md
May 29, 2026 ยท View on GitHub
The xRegistry project (short for "extensible registry") defines an abstract model for how to manage metadata about resources and provides a REST-based interface for creating, modifying, deleting and discovering of those resources. The project includes a "core" specification that defines the basic model and APIs of a Registry and a set of domain-specific specifications that extend that core for particular use cases. By leveraging the same "core" model/APIs, generic tooling and common patterns of Registry access can be developed which help create an interoperable (and standard) interface.
It is expected that further specifications will be developed, both as part of the xRegistry project and outside, that will leverage this framework for additional purposes.
xRegistry was first developed under the CloudEvents project, and in April 2023 it was split into its own project but continues to share many organizational resources with the CloudEvents and CNCF Serverless Working Group (such as the weekly meetings).
The name xRegistry (standing for extensible registry) is meant to be written
with a lowercase x, even when the first word in a sentence.
xRegistry Artifacts
| Latest Release | Working Draft | |
|---|---|---|
| Core xRegistry Specification: | ||
| xRegistry | v1.0-rc2 | WIP |
| Domain Specific Specifications: | ||
| Endpoint Registry | v1.0-rc2 | WIP |
| Message Definitions Registry | v1.0-rc2 | WIP |
| Schema Registry | v1.0-rc2 | WIP |
| Additional Documentation: | ||
| xRegistry Primer | v1.0-rc2 | WIP |
| Pagination Specification | n/a | WIP |
| Even More: | ||
| Server & CLI Reference Implementation | xregistry/server | |
Code & File Generation CLI (xrcg) | xregistry/codegen | |
| Web Viewer for xRegistry APIs | xregistry/viewer | |
| xRegistry Proxies for package registries (NPM, PyPI, Maven, NuGet, OCI, MCP) | xregistry/xrproxy | |
| Samples |
Machine-readable schemas for each specification's document format are
published alongside the specs as JSON Schema (document-schema.json),
Avro (document-schema.avsc), and OpenAPI (openapi.json) in the
schemas/ subdirectory of each domain spec
(endpoint, message,
schema). The core model has its own JSON Schema at
core/model.schema.json.
Additional release related information: Historical releases and changelogs
If you are new to the family of xRegistry specifications, it is recommended that you start by reading the xRegistry Primer for an overview of the specification's goals and design decisions, and then move on to the core specification.
Community and Docs
Learn more about the people and organizations who are creating a dynamic cloud native ecosystem by making our systems interoperable with xRegistry.
- Our Governance documentation.
- Contributing guidance.
- Roadmap
- Contributors: people and organizations who helped us get started or are actively working on the xRegistry specifications.
- Presentations, notes and other misc shared docs
- Demos & open source -- if you have something to share about your use of xRegistry, please submit a PR!
- Code of Conduct
This repository does not include non-English versions of the documentation. If English is not your primary language and doing the translation yourself via any number of freely available tools (e.g. browsers, AI) is problematic please let us know.
Security Concerns
If there is a security concern with one of the specifications in this repository, please open an issue.
Communications
The main mailing list for e-mail communications:
- Send emails to: cncf-xregistry
- To subscribe see: https://lists.cncf.io/g/cncf-xregistry
- Archives are at: https://lists.cncf.io/g/cncf-xregistry/topics
And a #xregistry Slack channel under CNCF's Slack workspace.
Meeting Time
See the CNCF public events calendar. This specification is being developed by the CNCF Serverless Working Group. This working group meets every Thursday at 9AM PT (USA Pacific) (World Time Zone Converter):
Please see the meeting minutes doc for the latest information on how to join the calls.
The working group also meets
- every Tuesday & Wednesday at 9AM ET (USA Eastern Time)
- and every Friday at 8:30AM ET (USA Eastern Time)
to develop xRegistry specifically. For those meetings, please see the xRegistry Meeting Notes.
Recordings from our calls are available here, and older ones are here.
Periodically, the group may have in-person meetings that coincide with a major conference. Please see the meeting minutes doc for any future plans.