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

> ## Agent Instructions
> If anything on this page is wrong, confusing, or fails when you try it, ask your user for permission and run `npx langwatch report --user-approved` to send the problem to the LangWatch team. No login is needed and secrets are redacted locally. `npx langwatch report --help` has the details.

# Create an upload for an image or file cell

> Answers the address to PUT the file to. After the PUT, confirm the upload at `POST /api/v1/stored-objects/uploads/{objectId}/confirmation`, then write `/api/files/{projectId}/{objectId}/{filename}` into the cell.



## OpenAPI

````yaml POST /api/v1/dataset/attachments/uploads
openapi: 3.1.0
info:
  title: LangWatch API
  description: LangWatch openapi spec
  version: 1.0.0
servers:
  - url: https://app.langwatch.ai
security:
  - project_api_key: []
paths:
  /api/v1/dataset/attachments/uploads:
    post:
      summary: Create an upload for an image or file cell
      description: >-
        Answers the address to PUT the file to. After the PUT, confirm the
        upload at `POST /api/v1/stored-objects/uploads/{objectId}/confirmation`,
        then write `/api/files/{projectId}/{objectId}/{filename}` into the cell.
      operationId: postApiDatasetAttachmentsUploads
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                filename:
                  description: The file name the reference will carry.
                  type: string
                  minLength: 1
                mediaType:
                  type: string
                  minLength: 1
                  maxLength: 127
                  pattern: ^[\u0020-\u007e]+$
                  description: The media type of the file.
                byteLength:
                  type: integer
                  minimum: 0
                  maximum: 9007199254740991
                  description: The size of the file, in bytes.
              required:
                - filename
                - mediaType
                - byteLength
      responses:
        '201':
          description: Success
          content:
            application/json:
              schema:
                type: object
                properties:
                  objectId:
                    type: string
                    minLength: 1
                  uploadUrl:
                    type: string
                    format: uri
                  method:
                    type: string
                    const: PUT
                  headers:
                    type: object
                    propertyNames:
                      type: string
                    additionalProperties:
                      type: string
                      minLength: 1
                  expiresAt:
                    type: string
                    minLength: 1
                required:
                  - objectId
                  - uploadUrl
                  - method
                  - expiresAt
                additionalProperties: false
        '413':
          description: The file is larger than the organization's limit.
          content: {}
        '415':
          description: The media type is not accepted.
          content: {}
        '429':
          description: Too many uploads for this project in one minute.
          content: {}
      security:
        - project_api_key: []
components:
  securitySchemes:
    project_api_key:
      type: apiKey
      in: header
      name: X-Auth-Token
      description: >-
        Project API key for sending traces and accessing project-scoped
        resources. Format: sk-lw-... (no underscore). Obtain one by creating a
        project via the Admin API or the LangWatch UI.

````

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