WunderGraph Feature Subgraphs API

openapi: 3.2.0
info:
  title: WunderGraph Cosmo Platform Analytics Feature Subgraphs API
  description: The WunderGraph Cosmo Platform API provides programmatic access to manage federated GraphQL architectures at scale. It powers the Cosmo CLI (wgc) and Cosmo Studio, enabling management of federated graphs, subgraphs, namespaces, schema contracts, feature flags, router configurations, and API keys. The API uses Connect-RPC protocol with HTTP/JSON support. Cosmo is the open-source alternative to Apollo GraphOS for full lifecycle GraphQL federation management including schema registry, composition checks, analytics, metrics, tracing, and routing.
  version: 1.0.0
  contact:
    name: WunderGraph
    url: https://wundergraph.com
  license:
    name: Apache 2.0
    url: https://www.apache.org/licenses/LICENSE-2.0
servers:
- url: https://cosmo-cp.wundergraph.com
  description: WunderGraph Cosmo Cloud Control Plane
tags:
- name: Feature Subgraphs
  description: Manage feature subgraphs for experimental feature development.
paths:
  /v1/feature-subgraphs:
    post:
      operationId: createFeatureSubgraph
      summary: WunderGraph Create a feature subgraph
      description: Creates a feature subgraph based on an existing subgraph for gradual and experimental feature rollout using feature flags.
      tags:
      - Feature Subgraphs
      security:
      - apiKey: []
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              required:
              - name
              - baseSubgraphName
              properties:
                name:
                  type: string
                  description: The name of the feature subgraph.
                namespace:
                  type: string
                  description: The namespace for the feature subgraph.
                baseSubgraphName:
                  type: string
                  description: The name of the base subgraph this feature is based on.
                routingUrl:
                  type: string
                  format: uri
                  description: The routing URL for the feature subgraph.
      responses:
        '200':
          description: Feature subgraph created successfully
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/OperationResponse'
components:
  schemas:
    OperationResponse:
      type: object
      properties:
        success:
          type: boolean
          description: Whether the operation was successful.
        message:
          type: string
          description: A human-readable response message.
  securitySchemes:
    apiKey:
      type: apiKey
      in: header
      name: Authorization
      description: API key for authenticating with the Cosmo Platform API. Obtain via Cosmo Studio or wgc CLI. Set as COSMO_API_KEY environment variable.
x-authored-by: API Evangelist
x-modeled-from: documentation
x-provenance:
  method: modeled
  authored_by: API Evangelist
  modeled_from: https://cosmo-docs.wundergraph.com/
  provider_published: false
  note: Modeled by API Evangelist from WunderGraph's public Cosmo documentation. The provider does not publish a REST OpenAPI. The real control-plane interface is Connect-RPC, defined in WunderGraph's own platform.proto — see grpc/ for the verbatim first-party contract, which is authoritative where this document and the proto disagree.
  verified: '2026-08-03'
  evidence:
  - url: https://cosmo-cp.wundergraph.com/openapi.json
    status: 404
    note: no provider-published OpenAPI at the control-plane host
  - url: https://cosmo-cp.wundergraph.com/v1/analytics
    status: 404
    note: REST path modeled in this document does not resolve
  - url: https://cosmo-cp.wundergraph.com/wg.cosmo.platform.v1.PlatformService/GetFederatedGraphs
    status: 200
    method: POST
    note: the surface that does exist — Connect-RPC, not REST