diff --git a/extensions/workspaces/README.md b/extensions/workspaces/README.md
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+# Workspaces Extension
+
+The Workspace Extension to the openEO API provides an interface for connecting external file storage such as cloud buckets to openEO back-end implementations.
+It also allows to register such file storage as a data source for new collections, so-called "User Collections".
+
+- Version: **0.1.0**
+- Stability: **experimental**
+- [OpenAPI document](openapi.yaml)
+- Conformance class: `https://api.openeo.org/extensions/workspaces/0.1.0`
+
+**Note:** This document only documents the additions to the specification.
+Extensions can not change or break existing behavior of the openEO API.
+
diff --git a/extensions/workspaces/openapi.yaml b/extensions/workspaces/openapi.yaml
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+openapi: 3.0.2
+info:
+  title: openEO API - Workspaces Extension
+  version: 0.1.0
+  description: |-
+    The Workspaces Extension to the openEO API provides an interface for connecting external file storage such as cloud buckets to openEO back-end implementations.
+
+    It also allows to register such file storage as a data source for new collections, so-called "User Collections".
+  contact:
+    name: openEO Consortium
+    url: 'https://openeo.org'
+    email: openeo.psc@uni-muenster.de
+  license:
+    name: Apache 2.0
+    url: 'http://www.apache.org/licenses/LICENSE-2.0.html'
+externalDocs:
+  url: https://github.com/Open-EO/openeo-api/blob/draft/extensions/workspaces/README.md
+tags:
+  - name: Workspaces
+    description: Management of User Workspaces
+  - name: User Collections
+    description: Management of User Collections
+servers:
+  - url: 'https://openeo.example/api/{version}'
+    description: >-
+      The URL of the API MAY freely be chosen by the back-end providers. The
+      path, including API versioning, is a *recommendation* only. Nevertheless,
+      all servers MUST support HTTPS as the authentication methods are not
+      secure with HTTP only!
+    variables:
+      version:
+        default: v1
+        description: >-
+          API versioning is RECOMMENDED. As the openEO API is following
+          [SemVer](https://semver.org/) only the MAJOR part of the stable
+          version numbers (i.e. versions >= 1.0.0) SHOULD be used for API
+          versioning in the URL. The reason is that backward-incompatible
+          changes are usually introduced by major changes. Therefore, the
+          version number in the URL MUST not be used by the clients to detect
+          the version number of the API. Use the version number returned from
+          `GET /` instead.
+paths:
+  /workspaces:
+    post:
+      summary: Create Workspace
+      operationId: create_workspace_workspaces_post
+      parameters:
+        - required: false
+          schema:
+            title: Authorization
+            type: string
+          name: authorization
+          in: header
+      requestBody:
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/WorkspaceCreate'
+        required: true
+      responses:
+        '201':
+          description: Successful Response
+          content:
+            application/json:
+              schema: {}
+        '422':
+          description: Validation Error
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/HTTPValidationError'
+  /workspaces/{workspace_name}:
+    get:
+      summary: Get Workspace
+      operationId: get_workspace_workspaces__workspace_name__get
+      parameters:
+        - required: true
+          schema:
+            title: Workspace Name
+            pattern: ^demo-user
+            type: string
+          name: workspace_name
+          in: path
+      responses:
+        '200':
+          description: Successful Response
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Workspace'
+        '422':
+          description: Validation Error
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/HTTPValidationError'
+    delete:
+      summary: Delete Workspace
+      operationId: delete_workspace_workspaces__workspace_name__delete
+      parameters:
+        - required: true
+          schema:
+            title: Workspace Name
+            pattern: ^demo-user
+            type: string
+          name: workspace_name
+          in: path
+      responses:
+        '204':
+          description: Successful Response
+        '422':
+          description: Validation Error
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/HTTPValidationError'
+    patch:
+      summary: Patch Workspace
+      operationId: patch_workspace_workspaces__workspace_name__patch
+      parameters:
+        - required: true
+          schema:
+            title: Workspace Name
+            pattern: ^demo-user
+            type: string
+          name: workspace_name
+          in: path
+      requestBody:
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/WorkspaceUpdate'
+        required: true
+      responses:
+        '204':
+          description: Successful Response
+        '422':
+          description: Validation Error
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/HTTPValidationError'
+  /workspaces/{workspace_name}/register:
+    post:
+      summary: Register
+      operationId: register_workspaces__workspace_name__register_post
+      parameters:
+        - required: true
+          schema:
+            title: Workspace Name
+            pattern: ^demo-user
+            type: string
+          name: workspace_name
+          in: path
+      requestBody:
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/Product'
+        required: true
+      responses:
+        '200':
+          description: Successful Response
+          content:
+            application/json:
+              schema: {}
+        '422':
+          description: Validation Error
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/HTTPValidationError'
+  /workspaces/{workspace_name}/deregister:
+    post:
+      summary: Deregister
+      operationId: deregister_workspaces__workspace_name__deregister_post
+      parameters:
+        - required: true
+          schema:
+            title: Workspace Name
+            pattern: ^demo-user
+            type: string
+          name: workspace_name
+          in: path
+      requestBody:
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/DeregisterProduct'
+        required: true
+      responses:
+        '200':
+          description: Successful Response
+          content:
+            application/json:
+              schema: {}
+        '422':
+          description: Validation Error
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/HTTPValidationError'
+  /collections:
+    post:
+      summary: Register Collection
+      operationId: register_collection_workspaces__workspace_name__register_collection_post
+      parameters:
+        - required: true
+          schema:
+            title: Workspace Name
+            pattern: ^demo-user
+            type: string
+          name: workspace_name
+          in: path
+      requestBody:
+        content:
+          application/json:
+            schema:
+              title: Collection
+              type: object
+        required: true
+      responses:
+        '200':
+          description: Successful Response
+          content:
+            application/json:
+              schema: {}
+        '422':
+          description: Validation Error
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/HTTPValidationError'
+    delete:
+      summary: Unregister Collection
+      operationId: register_collection_workspaces__workspace_name__register_collection_post
+      parameters:
+        - required: true
+          schema:
+            title: Workspace Name
+            pattern: ^demo-user
+            type: string
+          name: workspace_name
+          in: path
+      requestBody:
+        content:
+          application/json:
+            schema:
+              title: Collection
+              type: object
+        required: true
+      responses:
+        '200':
+          description: Successful Response
+          content:
+            application/json:
+              schema: {}
+        '422':
+          description: Validation Error
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/HTTPValidationError'
+components:
+  schemas:
+    ContainerRegistryCredentials:
+      title: ContainerRegistryCredentials
+      required:
+        - username
+        - password
+      type: object
+      properties:
+        username:
+          title: Username
+          type: string
+        password:
+          title: Password
+          type: string
+    CreateContainerRegistryRepository:
+      title: CreateContainerRegistryRepository
+      required:
+        - repository_name
+      type: object
+      properties:
+        repository_name:
+          title: Repository Name
+          type: string
+    DeregisterProduct:
+      title: DeregisterProduct
+      required:
+        - type
+      type: object
+      properties:
+        type:
+          title: Type
+          type: string
+        identifier:
+          title: Identifier
+          type: string
+        url:
+          title: Url
+          type: string
+    Endpoint:
+      title: Endpoint
+      required:
+        - id
+        - url
+      type: object
+      properties:
+        id:
+          title: Id
+          type: string
+        url:
+          title: Url
+          type: string
+    GrantAccess:
+      title: GrantAccess
+      required:
+        - repository_name
+        - username
+      type: object
+      properties:
+        repository_name:
+          title: Repository Name
+          type: string
+        username:
+          title: Username
+          type: string
+    HTTPValidationError:
+      title: HTTPValidationError
+      type: object
+      properties:
+        detail:
+          title: Detail
+          type: array
+          items:
+            $ref: '#/components/schemas/ValidationError'
+    Product:
+      title: Product
+      required:
+        - type
+        - url
+      type: object
+      properties:
+        type:
+          title: Type
+          type: string
+        url:
+          title: Url
+          type: string
+        parent_identifier:
+          title: Parent Identifier
+          type: string
+    Storage:
+      title: Storage
+      required:
+        - credentials
+      type: object
+      properties:
+        credentials:
+          title: Credentials
+          type: object
+          additionalProperties:
+            type: string
+    StorageUpdate:
+      title: StorageUpdate
+      required:
+        - quota_in_mb
+      type: object
+      properties:
+        quota_in_mb:
+          title: Quota In Mb
+          type: integer
+    ValidationError:
+      title: ValidationError
+      required:
+        - loc
+        - msg
+        - type
+      type: object
+      properties:
+        loc:
+          title: Location
+          type: array
+          items:
+            anyOf:
+              - type: string
+              - type: integer
+        msg:
+          title: Message
+          type: string
+        type:
+          title: Error Type
+          type: string
+    Workspace:
+      title: Workspace
+      required:
+        - status
+      type: object
+      properties:
+        status:
+          $ref: '#/components/schemas/WorkspaceStatus'
+        endpoints:
+          title: Endpoints
+          type: array
+          items:
+            $ref: '#/components/schemas/Endpoint'
+          default: []
+        storage:
+          $ref: '#/components/schemas/Storage'
+        container_registry:
+          $ref: '#/components/schemas/ContainerRegistryCredentials'
+    WorkspaceCreate:
+      title: WorkspaceCreate
+      type: object
+      properties:
+        preferred_name:
+          title: Preferred Name
+          type: string
+          default: ''
+        default_owner:
+          title: Default Owner
+          type: string
+          default: ''
+    WorkspaceStatus:
+      title: WorkspaceStatus
+      enum:
+        - ready
+        - provisioning
+      description: An enumeration.
+    WorkspaceUpdate:
+      title: WorkspaceUpdate
+      type: object
+      properties:
+        storage:
+          $ref: '#/components/schemas/StorageUpdate'
diff --git a/extensions/workspaces/package.json b/extensions/workspaces/package.json
new file mode 100644
index 00000000..e9e403c8
--- /dev/null
+++ b/extensions/workspaces/package.json
@@ -0,0 +1,24 @@
+{
+  "name": "@openeo/api-extension-commercial-data",
+  "version": "0.1.0",
+  "author": "openEO Consortium",
+  "license": "Apache-2.0",
+  "description": "The openEO API specification.",
+  "homepage": "https://openeo.org",
+  "bugs": {
+    "url": "https://github.com/Open-EO/openeo-api/issues"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/Open-EO/openeo-api.git"
+  },
+  "devDependencies": {
+    "@stoplight/spectral": "^5.9.1",
+    "redoc-cli": "^0.13.21"
+  },
+  "scripts": {
+    "start": "redoc-cli serve openapi.yaml --watch --options.expandResponses \"200,201,202,203,204\" --options.pathInMiddlePanel true",
+    "build": "redoc-cli bundle openapi.yaml -o redoc.html --title \"openEO API - Workspace Extension\" --cdn --options.expandResponses \"200,201,202,203,204\" --options.pathInMiddlePanel true",
+    "test": "spectral lint openapi.yaml"
+  }
+}