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@kcl-lang

The KCL Programming Language

KCL is an open-source constraint-based record & functional language mainly used in configuration and policy scenarios.

Hey, this is KCL community 👋

💻 Website | 👩‍💻 Quick Start | 👀 Blog | 📦 Modules | 🔧 SDKs | 🔌 Plugins | 💻 IDE Extensions | 🎮 Playground |☸️ KRM KCL Spec

KCL is a constraint-based record & functional language mainly used in cloud-native configuration and policy scenarios. It is hosted by the Cloud Native Computing Foundation (CNCF) as a Sandbox Project.

What is it for?

KCL aims to provide the following capabilities:

  • Hide infrastructure and platform details by defining more appropriate API abstractions to reduce the burden of developers.
  • Mutate and validate existing config files or manifests through numerous community modules.
  • Manage large-scale configuration data across teams without side effects through configuration and policy language for GitOps.

Specifically, KCL can

  • Improve the ability to semantically validate configurations at the code level, such as schema definitions, required/optional attribute requirements, types, range constraints, and etc.
  • Provide capabilities for writing, combining, and abstracting configuration chunks, such as structure definitions, structure inheritance, constraint definitions, and configuration policy merging.
  • Enhance configuration flexibility by adopting modern programming language features, such as conditional statements, loops, functions, and package management, to improve configuration reusability.
  • Provide comprehensive toolchain support, including rich IDE extensions and toolchains support to reduce the learning curve and enhance the user experience.
  • Enable easier sharing, propagation, and delivery of configurations between different teams/roles through package management tools and OCI registries.
  • Offer a high-performance compiler to meet the demands of scalable configuration scenarios, such as rendering performance for generating configurations for different environments and topologies based on a baseline configuration and configuration automation modification performance requirements.
  • Improve automation integration capabilities through multi-language SDKs, KCL language plugins, and other means, significantly reducing the learning curve while leveraging the value of configuration and policy writing with KCL.
  • Used as a platform engineering language to deliver modern apps with KusionStack.

Documents

See the KCL website for more information.

Community

See the community for ways to join us.

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  1. kcl kcl Public

    KCL Programming Language (CNCF Sandbox Project). https://kcl-lang.io

    Rust 2.1k 145

  2. modules modules Public

    KCL Community Modules. View on Artifact Hub: https://artifacthub.io/packages/search?org=kcl&sort=relevance&page=1

    Roff 31 41

  3. cli cli Public

    The KCL Command Line Interface (CLI).

    Go 30 19

  4. krm-kcl krm-kcl Public

    Kubernetes Resource Model KCL Specification and Integrations including Kubectl, Kustomize, Helm, Helmfile, Crossplane, KPT, etc.

    Go 26 16

  5. kcl-lang.io kcl-lang.io Public

    KCL Website and Documentation Repo

    TypeScript 18 49

  6. lib lib Public

    KCL Multiple Language Bindings including Rust, Go, Python, Java, Kotlin, .NET, Swift, Lua, Node.js, Zig, C, C++, WASM, etc.

    C# 11 11

Repositories

Showing 10 of 45 repositories
  • helm-kcl Public

    Helm KCL Plugin

    kcl-lang/helm-kcl’s past year of commit activity
    Go 17 Apache-2.0 4 2 1 Updated Sep 2, 2025
  • flux-kcl-controller Public

    Flux KCL Controller

    kcl-lang/flux-kcl-controller’s past year of commit activity
    Go 27 Apache-2.0 9 6 (3 issues need help) 3 Updated Sep 2, 2025
  • kpm Public

    KCL Package Manager

    kcl-lang/kpm’s past year of commit activity
    Go 36 Apache-2.0 60 14 (5 issues need help) 6 Updated Sep 2, 2025
  • krm-kcl Public

    Kubernetes Resource Model KCL Specification and Integrations including Kubectl, Kustomize, Helm, Helmfile, Crossplane, KPT, etc.

    kcl-lang/krm-kcl’s past year of commit activity
    Go 26 Apache-2.0 16 0 3 Updated Sep 2, 2025
  • cli Public

    The KCL Command Line Interface (CLI).

    kcl-lang/cli’s past year of commit activity
    Go 30 Apache-2.0 19 10 5 Updated Sep 1, 2025
  • modules Public

    KCL Community Modules. View on Artifact Hub: https://artifacthub.io/packages/search?org=kcl&sort=relevance&page=1

    kcl-lang/modules’s past year of commit activity
    Roff 31 Apache-2.0 41 8 1 Updated Sep 1, 2025
  • kcl-go Public

    KCL Go SDK

    kcl-lang/kcl-go’s past year of commit activity
    Go 53 Apache-2.0 29 6 (2 issues need help) 0 Updated Aug 28, 2025
  • lib Public

    KCL Multiple Language Bindings including Rust, Go, Python, Java, Kotlin, .NET, Swift, Lua, Node.js, Zig, C, C++, WASM, etc.

    kcl-lang/lib’s past year of commit activity
    C# 11 Apache-2.0 11 6 2 Updated Aug 28, 2025
  • kubectl-kcl Public

    Kubectl KCL Plugin

    kcl-lang/kubectl-kcl’s past year of commit activity
    Go 15 Apache-2.0 4 3 1 Updated Aug 28, 2025
  • kcl-openapi Public

    KCL OpenAPI Integration

    kcl-lang/kcl-openapi’s past year of commit activity
    Go 8 Apache-2.0 8 5 (1 issue needs help) 4 Updated Aug 26, 2025