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

# Get Multipart Part URL

> Presign one part of an in-flight multipart upload. Part numbers start at 1; every part except the last must be at least 5 MiB. Capture the `ETag` response header from each part `PUT` — Complete Multipart Upload needs it.



## OpenAPI

````yaml /platform-openapi.json get /storage/upload/multipart-url
openapi: 3.1.0
info:
  title: ModelRunner Platform API
  version: 1.0.0
  description: >-
    Platform APIs: model catalog, search and collections; model pricing rate
    cards; the Serverless GPU catalog and deployment templates; file uploads and
    your asset library; account balance and usage; and webhook delivery
    management. Catalog reads are public; account-scoped routes authenticate
    with your API key (`Authorization: Key <MODELRUNNER_KEY>`). Request
    lifecycle endpoints (submit/status/result and the request list) live on the
    queue host — see the Queue API reference.
servers:
  - url: https://api.modelrunner.run
security: []
paths:
  /storage/upload/multipart-url:
    get:
      summary: Get Multipart Part URL
      description: >-
        Presign one part of an in-flight multipart upload. Part numbers start at
        1; every part except the last must be at least 5 MiB. Capture the `ETag`
        response header from each part `PUT` — Complete Multipart Upload needs
        it.
      parameters:
        - name: uploadKey
          in: query
          required: true
          schema:
            type: string
        - name: uploadId
          in: query
          required: true
          schema:
            type: string
        - name: partNumber
          in: query
          required: true
          schema:
            type: integer
            minimum: 1
      responses:
        '200':
          description: Presigned part upload URL.
          content:
            application/json:
              schema:
                type: object
                properties:
                  presignedUrl:
                    type: string
        '401':
          description: Missing or invalid credentials.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
      security:
        - apiKeyAuth: []
components:
  schemas:
    ErrorResponse:
      type: object
      properties:
        error:
          type: string
          description: Human-readable error message.
        request_id:
          type: string
          description: Correlation id for support.
  securitySchemes:
    apiKeyAuth:
      type: apiKey
      in: header
      name: Authorization
      description: 'Use the format: Key modelrunner_key'

````