resources/uploads/subresources/parts/methods/create/index.md 2026-07-10 23:02 UTC to 2026-07-12 06:58 UTC

Add upload part

post /uploads/{upload_id}/parts

Adds a Part to an Upload object. A Part represents a chunk of bytes from the file you are trying to upload.

Each Part can be at most 64 MB, and you can add Parts until you hit the Upload maximum of 8 GB.

It is possible to add multiple Parts in parallel. You can decide the intended order of the Parts when you complete the Upload.

Path Parameters

• upload_id: string

Returns

• UploadPart object { id, created_at, object, upload_id }

  The upload Part represents a chunk of bytes we can add to an Upload object.

  • id: string

    The upload Part unique identifier, which can be referenced in API endpoints.

  • created_at: number

    The Unix timestamp (in seconds) for when the Part was created.

  • object: "upload.part"

    The object type, which is always upload.part.

    • "upload.part"

  • upload_id: string

    The ID of the Upload object that this Part was added to.

Example

curl https://api.openai.com/v1/uploads/$UPLOAD_ID/parts \
    -H 'Content-Type: multipart/form-data' \
    -H "Authorization: Bearer $OPENAI_API_KEY" \
    -F 'data=@/path/to/data'

Response

{
  "id": "id",
  "created_at": 0,
  "object": "upload.part",
  "upload_id": "upload_id"
}

Example

curl https://api.openai.com/v1/uploads/upload_abc123/parts
  -F data="aHR0cHM6Ly9hcGkub3BlbmFpLmNvbS92MS91cGxvYWRz..."

Response

{
  "id": "part_def456",
  "object": "upload.part",
  "created_at": 1719185911,
  "upload_id": "upload_abc123"
}