> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/makenotion/notion-sdk-js/llms.txt
> Use this file to discover all available pages before exploring further.

# Send file upload

> Upload file data for a created file upload

Sends file data to a previously created file upload. This endpoint accepts `multipart/form-data` instead of JSON.

## Method

```typescript theme={null}
client.fileUploads.send({
  file_upload_id: "file_upload_id",
  file: {
    data: fileBuffer,
    filename: "document.pdf"
  }
})
```

## Parameters

<ParamField path="file_upload_id" type="string" required>
  Identifier for a Notion file upload object, obtained from the `id` of the [Create File Upload](/api/file-uploads/create) response.
</ParamField>

<ParamField path="file" type="object" required>
  The file data to upload.

  <ParamField path="file.data" type="string | Blob" required>
    Raw file contents as a string, Buffer, Blob, or File object.
  </ParamField>

  <ParamField path="file.filename" type="string">
    Optional filename. Overrides the filename specified in create.
  </ParamField>
</ParamField>

<ParamField path="part_number" type="string">
  Required for multi-part uploads. Stringified integer (e.g., `"1"`, `"2"`, `"3"`) indicating which part is being sent. Must be sequential starting from `"1"` and match the `number_of_parts` specified in create.
</ParamField>

## Response

Returns an updated [FileUpload object](/api/file-uploads#file-upload-object).

<ResponseField name="status" type="string">
  Updated status: `"pending"` (for multi-part, more parts needed) or `"uploaded"` (for single-part, or after all parts sent and complete called).
</ResponseField>

<ResponseField name="number_of_parts" type="object">
  For multi-part uploads, tracks progress:

  * `total`: Total number of parts expected
  * `sent`: Number of parts successfully uploaded
</ResponseField>

<ResponseField name="file_import_result" type="object">
  After successful upload, contains import results:

  * `type`: `"success"` or `"error"`
  * `imported_time`: ISO 8601 timestamp
  * `error`: Error details if type is `"error"`
</ResponseField>

## Examples

### Single-part upload

For files under 20MB, send all data in one request:

```typescript theme={null}
import fs from "fs"

// First, create the file upload
const fileUpload = await client.fileUploads.create({
  mode: "single_part",
  filename: "report.pdf",
  content_type: "application/pdf"
})

// Then send the file data
const fileBuffer = fs.readFileSync("./report.pdf")

const result = await client.fileUploads.send({
  file_upload_id: fileUpload.id,
  file: {
    data: fileBuffer,
    filename: "report.pdf"
  }
})

console.log(result.status) // "uploaded"
```

### Multi-part upload

For files larger than 20MB, split into parts and send sequentially:

```typescript theme={null}
import fs from "fs"

const CHUNK_SIZE = 20 * 1024 * 1024 // 20MB per part
const fileBuffer = fs.readFileSync("./large-video.mp4")
const totalParts = Math.ceil(fileBuffer.length / CHUNK_SIZE)

// Create the upload
const fileUpload = await client.fileUploads.create({
  mode: "multi_part",
  filename: "large-video.mp4",
  content_type: "video/mp4",
  number_of_parts: totalParts
})

// Send each part sequentially
for (let i = 0; i < totalParts; i++) {
  const start = i * CHUNK_SIZE
  const end = Math.min(start + CHUNK_SIZE, fileBuffer.length)
  const chunk = fileBuffer.slice(start, end)
  
  await client.fileUploads.send({
    file_upload_id: fileUpload.id,
    file: {
      data: chunk,
      filename: "large-video.mp4"
    },
    part_number: String(i + 1) // Must be a string: "1", "2", "3", etc.
  })
  
  console.log(`Sent part ${i + 1} of ${totalParts}`)
}

// Finally, complete the upload
await client.fileUploads.complete({
  file_upload_id: fileUpload.id
})
```

### Browser file upload

Using the File API in browsers:

```typescript theme={null}
// In a browser environment
const handleFileUpload = async (file: File) => {
  // Create the upload
  const fileUpload = await client.fileUploads.create({
    mode: "single_part",
    filename: file.name,
    content_type: file.type
  })
  
  // Send the file (File object is a type of Blob)
  const result = await client.fileUploads.send({
    file_upload_id: fileUpload.id,
    file: {
      data: file,
      filename: file.name
    }
  })
  
  return result
}
```

## Notes

* This endpoint sends HTTP `multipart/form-data` instead of JSON
* For multi-part uploads, parts must be sent sequentially starting from `"1"`
* The `part_number` parameter must be a **string**, not a number
* After sending all parts, call [complete](/api/file-uploads/complete) to finalize the upload
* File data is passed under the `file.data` property, not as the raw file

## Related

* [Create file upload](/api/file-uploads/create) - Initialize upload
* [Complete file upload](/api/file-uploads/complete) - Finalize multi-part upload
* [List file uploads](/api/file-uploads/list) - Track upload status