Jump to Content

Class UploadPartCommandProtected

Uploads a part in a multipart upload.

In this operation, you provide part data in your request. However, you have an option to specify your existing Amazon S3 object as a data source for the part you are uploading. To upload a part from an existing object, you use the UploadPartCopy operation.

You must initiate a multipart upload (see CreateMultipartUpload) before you can upload any part. In response to your initiate request, Amazon S3 returns an upload ID, a unique identifier, that you must include in your upload part request.

Part numbers can be any number from 1 to 10,000, inclusive. A part number uniquely identifies a part and also defines its position within the object being created. If you upload a new part using the same part number that was used with a previous part, the previously uploaded part is overwritten.

For information about maximum and minimum part sizes and other multipart upload specifications, see Multipart upload limits in the Amazon S3 User Guide.

To ensure that data is not corrupted when traversing the network, specify the Content-MD5 header in the upload part request. Amazon S3 checks the part data against the provided MD5 value. If they do not match, Amazon S3 returns an error.

If the upload request is signed with Signature Version 4, then Amazon Web Services S3 uses the x-amz-content-sha256 header as a checksum instead of Content-MD5. For more information see Authenticating Requests: Using the Authorization Header (Amazon Web Services Signature Version 4).

Note: After you initiate multipart upload and upload one or more parts, you must either complete or abort multipart upload in order to stop getting charged for storage of the uploaded parts. Only after you either complete or abort multipart upload, Amazon S3 frees up the parts storage and stops charging you for the parts storage.

For more information on multipart uploads, go to Multipart Upload Overview in the Amazon S3 User Guide .

For information on the permissions required to use the multipart upload API, go to Multipart Upload and Permissions in the Amazon S3 User Guide.

You can optionally request server-side encryption where Amazon S3 encrypts your data as it writes it to disks in its data centers and decrypts it for you when you access it. You have the option of providing your own encryption key, or you can use the Amazon Web Services managed encryption keys. If you choose to provide your own encryption key, the request headers you provide in the request must match the headers you used in the request to initiate the upload by using CreateMultipartUpload. For more information, go to Using Server-Side Encryption in the Amazon S3 User Guide.

Server-side encryption is supported by the S3 Multipart Upload actions. Unless you are using a customer-provided encryption key, you don't need to specify the encryption parameters in each UploadPart request. Instead, you only need to specify the server-side encryption parameters in the initial Initiate Multipart request. For more information, see CreateMultipartUpload.

If you requested server-side encryption using a customer-provided encryption key in your initiate multipart upload request, you must provide identical encryption information in each part upload using the following headers.

  • x-amz-server-side-encryption-customer-algorithm

  • x-amz-server-side-encryption-customer-key

  • x-amz-server-side-encryption-customer-key-MD5

Special Errors

    • Code: NoSuchUpload

    • Cause: The specified multipart upload does not exist. The upload ID might be invalid, or the multipart upload might have been aborted or completed.

    • HTTP Status Code: 404 Not Found

    • SOAP Fault Code Prefix: Client

Related Resources


Use a bare-bones client and the command you need to make an API call.

import { S3Client, UploadPartCommand } from "@aws-sdk/client-s3"; // ES Modules import
// const { S3Client, UploadPartCommand } = require("@aws-sdk/client-s3"); // CommonJS import
const client = new S3Client(config);
const input = {
Bucket: "STRING_VALUE", // required
ContentLength: Number("long"),
ChecksumAlgorithm: "CRC32" || "CRC32C" || "SHA1" || "SHA256",
ChecksumCRC32: "STRING_VALUE",
ChecksumSHA256: "STRING_VALUE",
Key: "STRING_VALUE", // required
PartNumber: Number("int"), // required
UploadId: "STRING_VALUE", // required
SSECustomerAlgorithm: "STRING_VALUE",
RequestPayer: "requester",
ExpectedBucketOwner: "STRING_VALUE",
const command = new UploadPartCommand(input);
const response = await client.send(command);







To upload a part

// The following example uploads part 1 of a multipart upload. The example specifies a file name for the part data. The Upload ID is same that is returned by the initiate multipart upload.
const input = {
"Body": "fileToUpload",
"Bucket": "examplebucket",
"Key": "examplelargeobject",
"PartNumber": "1",
"UploadId": "xadcOB_7YPBOJuoFiQ9cz4P3Pe6FIZwO4f7wN93uHsNBEw97pl5eNwzExg0LAT2dUN91cOmrEQHDsP3WA60CEg--"
const command = new UploadPartCommand(input);
const response = await client.send(command);
/* response ==
"ETag": "\"d8c2eafd90c266e19ab9dcacc479f8af\""
// example id: to-upload-a-part-1481847914943




middlewareStack: MiddlewareStack<UploadPartCommandInput, UploadPartCommandOutput>