> ## Documentation Index
> Fetch the complete documentation index at: https://docs.lumenaza.de/llms.txt
> Use this file to discover all available pages before exploring further.

# Get v3validationpreferred delivery start



## OpenAPI

````yaml /lumx_openapi.yaml get /v3/validation/preferred_delivery_start/
openapi: 3.0.3
info:
  title: Lumenaza external API
  version: 3.8.0 (v3)
  description: Specification of the Lumenaza external API.
servers:
  - url: https://api.lumenaza.de/
    description: Produktivserver
  - url: https://api.test.lumenaza.de/
    description: Testserver
security: []
tags:
  - name: Community Data API
    description: >-
      The API is used to retrieve master data and measurement data for a
      community. A community is defined by all customers that belong to your
      company.
paths:
  /v3/validation/preferred_delivery_start/:
    get:
      tags:
        - validation
      operationId: validation_preferred_delivery_start_retrieve
      parameters:
        - in: query
          name: change_reason
          schema:
            enum:
              - E03
              - E01
              - E02
            type: string
            minLength: 1
          description: |-
            Subscription change reason.

            * `E03` - E03
            * `E01` - E01
            * `E02` - E02
          required: true
        - in: query
          name: customer_type
          schema:
            enum:
              - consumer
              - producer
            type: string
            minLength: 1
          description: |-
            Customer type for which the delivery start is validated.

            * `consumer` - consumer
            * `producer` - producer
          required: true
        - in: query
          name: has_intelligent_meter
          schema:
            type: boolean
            nullable: true
          description: Whether an intelligent meter is available.
        - in: query
          name: has_market_location
          schema:
            type: boolean
            nullable: true
          description: Whether a market location is already available.
        - in: query
          name: preferred_delivery_start
          schema:
            type: string
            format: date
          description: Requested delivery start date in YYYY-MM-DD format.
          required: true
        - in: query
          name: tariff_type
          schema:
            type: string
            minLength: 1
          description: >-
            Optional sales-partner product name; available values depend on the
            authenticated sales partner.
      responses:
        '200':
          description: The query parameters are valid; the response has no body.
        '400':
          content:
            application/json:
              schema:
                type: object
                additionalProperties: {}
              examples:
                UnknownCustomerTypeError:
                  value:
                    detail: unknown customer_type
                  summary: Unknown Customer Type Error
                UnsupportedChangeReasonError:
                  value:
                    detail: unsupported change_reason for selected customer_type
                  summary: Unsupported Change Reason Error
                DeliveryStartNotPossibleError:
                  value:
                    detail: delivery start to this date is not possible
                    earliest_possible_delivery_start: '2023-01-01'
                  summary: Delivery Start Not Possible Error
          description: DRF validation-error object keyed by invalid query parameters.

````

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