Helm Chart Repository API

openapi: 3.1.0
info:
  title: Helm Chart Repository API
  description: >-
    The Helm Chart Repository API defines the HTTP endpoints used by Helm
    clients to discover and download charts from a repository server. A chart
    repository is an HTTP server that houses an index.yaml file listing all
    available charts and optionally packaged chart archives (.tgz files).
    ChartMuseum and compatible implementations extend this with a JSON-based
    management API for listing, uploading, and deleting charts programmatically.
  version: v3.17.0
  contact:
    name: Helm Project
    url: https://helm.sh
  license:
    name: Apache 2.0
    url: https://www.apache.org/licenses/LICENSE-2.0
externalDocs:
  description: Helm Chart Repository Guide
  url: https://helm.sh/docs/topics/chart_repository/
servers:
  - url: 'https://{repository-host}'
    description: Helm Chart Repository Server
    variables:
      repository-host:
        default: charts.example.com
        description: The hostname of the chart repository
tags:
  - name: ChartMuseum
    description: >-
      Extended API endpoints provided by ChartMuseum and compatible chart
      repository servers for JSON-based chart management.
  - name: Charts
    description: >-
      Chart package download endpoints for retrieving packaged chart archives
      and provenance files for signature verification.
  - name: Repository
    description: >-
      Standard Helm chart repository endpoints for index and chart download.
      These endpoints are required for any Helm-compatible chart repository.
paths:
  /index.yaml:
    get:
      operationId: getRepositoryIndex
      summary: Helm Get repository index
      description: >-
        Retrieves the repository index file which contains metadata about all
        charts available in the repository. The index.yaml file lists every
        chart version along with its description, maintainers, download URLs,
        and content digests. Helm clients use this endpoint to search and
        resolve chart dependencies.
      tags:
        - Repository
      responses:
        '200':
          description: Repository index returned successfully
          content:
            application/x-yaml:
              schema:
                $ref: '#/components/schemas/RepositoryIndex'
            text/yaml:
              schema:
                $ref: '#/components/schemas/RepositoryIndex'
        '404':
          description: Repository index not found
  /charts/{chartName}-{version}.tgz:
    get:
      operationId: downloadChartPackage
      summary: Helm Download chart package
      description: >-
        Downloads a packaged Helm chart archive (.tgz file) for a specific chart
        name and version. The archive contains the Chart.yaml, values.yaml,
        templates, and other chart files. Helm clients use this endpoint after
        resolving chart references from the index.
      tags:
        - Charts
      parameters:
        - $ref: '#/components/parameters/ChartName'
        - $ref: '#/components/parameters/Version'
      responses:
        '200':
          description: Chart package returned successfully
          content:
            application/gzip:
              schema:
                type: string
                format: binary
            application/x-tar:
              schema:
                type: string
                format: binary
        '404':
          description: Chart package not found
  /charts/{chartName}-{version}.tgz.prov:
    get:
      operationId: downloadChartProvenance
      summary: Helm Download chart provenance file
      description: >-
        Downloads the provenance file for a specific chart version. The
        provenance file contains a PGP signature used to verify the integrity
        and origin of the chart package. This endpoint is optional and only
        available for cryptographically signed charts.
      tags:
        - Charts
      parameters:
        - $ref: '#/components/parameters/ChartName'
        - $ref: '#/components/parameters/Version'
      responses:
        '200':
          description: Provenance file returned successfully
          content:
            application/pgp-signature:
              schema:
                type: string
        '404':
          description: Provenance file not found
  /api/charts:
    get:
      operationId: listAllCharts
      summary: Helm List all charts
      description: >-
        Returns a list of all charts available in the repository grouped by
        chart name. This endpoint is provided by ChartMuseum and other enhanced
        chart repository implementations supporting JSON-based management.
      tags:
        - ChartMuseum
      responses:
        '200':
          description: Chart list returned successfully
          content:
            application/json:
              schema:
                type: object
                description: Map of chart names to their available versions.
                additionalProperties:
                  type: array
                  items:
                    $ref: '#/components/schemas/ChartVersion'
        '401':
          description: Unauthorized
    post:
      operationId: uploadChart
      summary: Helm Upload chart package
      description: >-
        Uploads a new chart package to the repository. This endpoint is provided
        by ChartMuseum and other writable chart repository implementations. The
        chart archive is sent as multipart form data or as a raw binary body.
      tags:
        - ChartMuseum
      requestBody:
        required: true
        content:
          multipart/form-data:
            schema:
              type: object
              properties:
                chart:
                  type: string
                  format: binary
                  description: The chart package archive (.tgz file)
                prov:
                  type: string
                  format: binary
                  description: Optional PGP provenance file (.tgz.prov)
      responses:
        '201':
          description: Chart uploaded successfully
          content:
            application/json:
              schema:
                type: object
                properties:
                  saved:
                    type: boolean
                    description: Whether the chart was saved successfully
                    example: true
        '401':
          description: Unauthorized
        '409':
          description: Chart version already exists
  /api/charts/{chartName}:
    get:
      operationId: getChartVersions
      summary: Helm Get chart versions
      description: >-
        Returns all available versions for a specific chart. This endpoint is
        provided by ChartMuseum and other enhanced chart repository
        implementations.
      tags:
        - ChartMuseum
      parameters:
        - $ref: '#/components/parameters/ChartName'
      responses:
        '200':
          description: Chart versions returned successfully
          content:
            application/json:
              schema:
                type: array
                items:
                  $ref: '#/components/schemas/ChartVersion'
        '401':
          description: Unauthorized
        '404':
          description: Chart not found
  /api/charts/{chartName}/{version}:
    get:
      operationId: getChartVersion
      summary: Helm Get specific chart version
      description: >-
        Returns metadata for a specific version of a named chart. This endpoint
        is provided by ChartMuseum and other enhanced chart repository
        implementations.
      tags:
        - ChartMuseum
      parameters:
        - $ref: '#/components/parameters/ChartName'
        - $ref: '#/components/parameters/Version'
      responses:
        '200':
          description: Chart version metadata returned successfully
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ChartVersion'
        '401':
          description: Unauthorized
        '404':
          description: Chart version not found
    delete:
      operationId: deleteChartVersion
      summary: Helm Delete chart version
      description: >-
        Deletes a specific version of a chart from the repository. This endpoint
        is provided by ChartMuseum and other writable chart repository
        implementations.
      tags:
        - ChartMuseum
      parameters:
        - $ref: '#/components/parameters/ChartName'
        - $ref: '#/components/parameters/Version'
      responses:
        '200':
          description: Chart version deleted successfully
          content:
            application/json:
              schema:
                type: object
                properties:
                  deleted:
                    type: boolean
                    description: Whether the chart version was deleted
                    example: true
        '401':
          description: Unauthorized
        '404':
          description: Chart version not found
  /api/prov:
    post:
      operationId: uploadProvenance
      summary: Helm Upload provenance file
      description: >-
        Uploads a PGP provenance file to the repository independently of a
        chart package. This endpoint is provided by ChartMuseum for cases where
        chart and provenance files are uploaded separately.
      tags:
        - ChartMuseum
      requestBody:
        required: true
        content:
          multipart/form-data:
            schema:
              type: object
              properties:
                prov:
                  type: string
                  format: binary
                  description: The PGP provenance file (.tgz.prov)
      responses:
        '201':
          description: Provenance file uploaded successfully
          content:
            application/json:
              schema:
                type: object
                properties:
                  saved:
                    type: boolean
                    description: Whether the provenance file was saved
                    example: true
        '401':
          description: Unauthorized
        '409':
          description: Provenance file already exists
  /health:
    get:
      operationId: getHealth
      summary: Helm Get repository health
      description: >-
        Returns the health status of the chart repository server. Useful for
        liveness and readiness probes in Kubernetes deployments.
      tags:
        - Repository
      responses:
        '200':
          description: Server is healthy
          content:
            application/json:
              schema:
                type: object
                properties:
                  healthy:
                    type: boolean
                    description: Whether the server is healthy
                    example: true
components:
  parameters:
    ChartName:
      name: chartName
      in: path
      required: true
      description: The name of the chart
      schema:
        type: string
        example: nginx
    Version:
      name: version
      in: path
      required: true
      description: The SemVer 2 version of the chart
      schema:
        type: string
        example: 1.2.3
  schemas:
    RepositoryIndex:
      type: object
      description: >-
        The repository index file listing all available charts and their
        versions. This is the primary discovery mechanism for Helm clients.
      required:
        - apiVersion
        - entries
      properties:
        apiVersion:
          type: string
          description: The API version of the index file format.
          example: v1
        generated:
          type: string
          format: date-time
          description: Timestamp when the index was last generated.
        entries:
          type: object
          description: >-
            Map of chart names to their available versions. Each key is a chart
            name and the value is an array of chart version metadata objects.
          additionalProperties:
            type: array
            items:
              $ref: '#/components/schemas/ChartVersion'
        serverInfo:
          type: object
          description: Optional server information included by some repository implementations.
          properties:
            contextPath:
              type: string
              description: Context path for the server.
    ChartVersion:
      type: object
      description: >-
        Metadata describing a specific version of a Helm chart as it appears
        in the repository index.
      required:
        - apiVersion
        - name
        - version
      properties:
        apiVersion:
          type: string
          description: The chart API version (v1 for Helm 2, v2 for Helm 3).
          enum:
            - v1
            - v2
          example: v2
        name:
          type: string
          description: The name of the chart.
          example: nginx
        version:
          type: string
          description: The SemVer 2 version of the chart.
          example: 1.2.3
        kubeVersion:
          type: string
          description: A SemVer range of compatible Kubernetes versions.
          example: '>= 1.19.0'
        description:
          type: string
          description: A single-sentence description of the chart.
        type:
          type: string
          description: The type of chart — application for installable charts, library for utility charts.
          enum:
            - application
            - library
          default: application
        keywords:
          type: array
          items:
            type: string
          description: Keywords associated with the chart for search and categorization.
        home:
          type: string
          format: uri
          description: The URL of the project home page.
        sources:
          type: array
          items:
            type: string
            format: uri
          description: URLs to source code for the chart.
        maintainers:
          type: array
          items:
            $ref: '#/components/schemas/Maintainer'
          description: List of chart maintainers.
        icon:
          type: string
          format: uri
          description: URL to an SVG or PNG icon for the chart.
        appVersion:
          type: string
          description: The version of the application contained in the chart.
          example: 1.21.0
        deprecated:
          type: boolean
          description: Whether this chart version is deprecated.
          default: false
        annotations:
          type: object
          additionalProperties:
            type: string
          description: >-
            Annotations are key-value pairs used by Artifact Hub and other tools
            for additional metadata.
        urls:
          type: array
          items:
            type: string
            format: uri
          description: Download URLs for the chart package.
        created:
          type: string
          format: date-time
          description: Timestamp when this version was added to the index.
        digest:
          type: string
          description: SHA-256 digest of the chart package for integrity verification.
          example: sha256:abc123def456
        dependencies:
          type: array
          items:
            $ref: '#/components/schemas/Dependency'
          description: List of chart dependencies declared in Chart.yaml.
    Maintainer:
      type: object
      description: Contact information for a chart maintainer.
      required:
        - name
      properties:
        name:
          type: string
          description: The maintainer name.
        email:
          type: string
          format: email
          description: The maintainer email address.
        url:
          type: string
          format: uri
          description: The maintainer URL.
    Dependency:
      type: object
      description: A chart dependency specifying another chart required by this chart.
      required:
        - name
        - version
      properties:
        name:
          type: string
          description: The name of the dependency chart.
        version:
          type: string
          description: The SemVer range for the dependency version.
        repository:
          type: string
          format: uri
          description: The URL of the chart repository where the dependency is hosted.
        condition:
          type: string
          description: >-
            A YAML path that resolves to a boolean to enable or disable the
            dependency.
        tags:
          type: array
          items:
            type: string
          description: Tags used to group dependencies for enable/disable.
        alias:
          type: string
          description: Alias name for the dependency chart.