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

# Upload one part for an outbound upload session

> Upload a single part (JSON array of objects). Part numbers are 1-based and must not exceed `totalParts`.



## OpenAPI

````yaml /api-reference/openapi.json put /outbound/uploads/{uploadId}/parts/{partNumber}
openapi: 3.0.3
info:
  title: FileFeed API
  version: '2026-05-25'
  description: >-
    Official FileFeed REST API for connections, pipelines, schemas, pipeline
    runs, webhooks, outbound uploads, documents, files, and notifications.
    Date-based API versioning is controlled by the `FileFeed-Version` request
    header (default `2024-09-01`; latest `2026-05-25`); this document describes
    the `2026-05-25` shape.
servers:
  - url: https://api.sftpsync.io
security:
  - ApiKeyAuth: []
tags:
  - name: Connections
  - name: Pipelines
  - name: Schemas
  - name: Pipeline Runs
  - name: Webhooks
  - name: Outbound Uploads
  - name: Documents
  - name: Files
  - name: Notifications
  - name: Clients (deprecated)
paths:
  /outbound/uploads/{uploadId}/parts/{partNumber}:
    put:
      tags:
        - Outbound Uploads
      summary: Upload one part for an outbound upload session
      description: >-
        Upload a single part (JSON array of objects). Part numbers are 1-based
        and must not exceed `totalParts`.
      operationId: uploadOutboundPart
      parameters:
        - name: uploadId
          in: path
          required: true
          schema:
            type: string
          description: Upload session ID from initUpload.
        - name: partNumber
          in: path
          required: true
          schema:
            type: integer
            minimum: 1
          description: 1-based part number.
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/UploadOutboundPartParams'
            example:
              data:
                - remoteId: E001
                  firstName: Alice
                  lastName: Smith
      responses:
        '200':
          description: Part uploaded
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/UploadOutboundPartResponse'
              example:
                uploadId: a1b2c3d4-e5f6-7890-abcd-ef1234567890
                partNumber: 1
                status: uploading
                uploadedParts: 1
                totalParts: 3
        '400':
          $ref: '#/components/responses/BadRequest'
        '404':
          $ref: '#/components/responses/NotFound'
components:
  schemas:
    UploadOutboundPartParams:
      type: object
      properties:
        data:
          type: array
          items:
            type: object
            additionalProperties: true
          description: Array of JSON objects for this part.
        checksum:
          type: string
          description: Optional checksum for integrity validation.
      required:
        - data
    UploadOutboundPartResponse:
      type: object
      properties:
        uploadId:
          type: string
        partNumber:
          type: integer
        status:
          $ref: '#/components/schemas/OutboundUploadState'
        uploadedParts:
          type: integer
          description: Number of parts uploaded so far.
        totalParts:
          type: integer
        etag:
          type: string
          description: Optional ETag for the uploaded part.
      required:
        - uploadId
        - partNumber
        - status
        - uploadedParts
        - totalParts
    OutboundUploadState:
      type: string
      enum:
        - initiated
        - uploading
        - completed
        - aborted
    ErrorResponse:
      type: object
      properties:
        message:
          type: string
        statusCode:
          type: integer
        error:
          type: string
  responses:
    BadRequest:
      description: Bad request
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
    NotFound:
      description: Not found
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
  securitySchemes:
    ApiKeyAuth:
      type: apiKey
      in: header
      name: x-api-key

````