> ## 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 Attachments

> Upload a file for an image or file column and get the reference a cell holds. The project is named by the `projectId` query parameter; the file goes in the `file` multipart field, with an optional `datasetId` field. create the upload, send the file to the address it answers, confirm it as a stored object, then put its reference in the cell



## OpenAPI

````yaml POST /api/v1/dataset/attachments
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:
    post:
      description: >-
        Upload a file for an image or file column and get the reference a cell
        holds. The project is named by the `projectId` query parameter; the file
        goes in the `file` multipart field, with an optional `datasetId` field.
        create the upload, send the file to the address it answers, confirm it
        as a stored object, then put its reference in the cell
      operationId: postApiDatasetAttachments
      parameters:
        - in: query
          name: projectId
          schema:
            type: string
            minLength: 1
          required: true
          description: The project the file is stored for.
      requestBody:
        required: true
        content:
          multipart/form-data:
            schema:
              type: object
              properties:
                datasetId:
                  description: >-
                    The dataset that owns the file. Omit it while the dataset is
                    still a draft.
                  type: string
                file:
                  type: string
                  format: binary
              required:
                - file
      responses:
        '200':
          description: Success
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/DatasetAttachment'
        '413':
          description: The file is larger than the upload limit.
          content: {}
        '415':
          description: The media type is not accepted.
          content: {}
        '429':
          description: Too many uploads for this project in one minute.
          content: {}
      deprecated: true
      security:
        - project_api_key: []
components:
  schemas:
    DatasetAttachment:
      type: object
      properties:
        url:
          type: string
          description: >-
            The value to write into the cell, and the address the file is served
            from.
        name:
          type: string
          description: The file name the reference carries.
        mediaType:
          type: string
          description: The media type the file is stored under.
        sizeBytes:
          type: number
          description: The size of the stored file, in bytes.
      required:
        - url
        - name
        - mediaType
        - sizeBytes
      additionalProperties: false
  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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