CUE reads, writes, and validates JSON data, regardless of its source: discrete JSON files, I/O streams, or JSON contained in data fields inside other formats. The cue command emits JSON by default.

CUE’s support for YAML mirrors its first class JSON support: it reads, writes and validates YAML data anywhere it can be found: discrete YAML files, I/O streams, or YAML contained in data fields inside other formats.

The cue command converts Go types to CUE, enabling their first class use as schema and data constraints. CUE’s extensive Go API allows code to have fine grained control over CUE’s capabilities and operations, including export to any encoding supported by CUE.

CUE reads and writes OpenAPI data schemas through its Go API and the cue command, enabling schemas to be used to constrain and validate data directly, and to be expressed in other formats - including CUE.

CUE’s Go API and the cue command read Protobuf definitions, enabling them to be used to constrain and validate data directly and to be expressed in other formats. CUE constraints can be extracted from Protobuf options, allowing richer data validation than Protobuf’s type-based defaults.

CUE understands JSON Schema constraints through its Go API and the cue command, enabling schemas to be used to constrain and validate data directly, and to be expressed in other formats - including CUE.

A worked example of converting a set of Kubernetes configuration files for a collection of microservices into smaller, validated CUE configurations by automatically removing boilerplate; automating commands that don’t know CUE yet (such as kubectl); and extracting schema definitions from Kubernetes source code.

A guide explaining how to convert GitHub Actions workflow files from YAML to CUE, check those workflows are valid, and then use CUE’s tooling layer to regenerate YAML - allowing safer and more predictable changes.

A pair of guides showing how to validate the JSON output from terraform plan using CUE as a policy language.

A guide that demonstrates how to use CUE to keep DNS data in a compact format, using CUE templating to DRY out configurations, and use CUE’s constraints to enforce policies on the data to guard against mistakes.

A guide illustrating how to convert a GitLab CI/CD pipeline file from YAML to CUE, check its contents are valid, and then use CUE’s tooling layer to regenerate YAML - allowing safer and more predictable changes.

A guide demonstrating how to convert static Buildkite pipelines files from YAML to CUE, check the pipelines are valid, and then use CUE’s tooling layer to regenerate YAML - allowing safer and more predictable changes by switching to CUE as a source of truth.

A guide that builds on an official Buildkite blog post, showing how to use CUE to define and validate CI pipelines as they’re initiated and as they’re executing, so that their steps can vary dynamically, based on the pipeline’s execution context.