startUpload method

Returns the ID that should be used in all subsequent operations for uploading objects.

If the object is to be stored with user-defined metadata, it should be passed in this request.


POST /{bucket}/{key}?uploads HTTP/1.1

Path parameters

Parameter Description
bucket Bucket name.
key Object key. The object will be saved in Object Storage under the specified name.

Query parameters

Parameter Description
uploads Flag indicating a multipart upload operation.


In a request, use the necessary common request headers.

You can also use the headers listed in the table below.

Header name Description
x-amz-meta-* User-defined metadata of the object.

Object Storage considers all headers starting with x-amz-meta- as user-defined. It does not process these headers, but saves them in the original form.

The total size of user-defined headers should not exceed 2 KB. The size of user-defined data is determined as the length of the UTF-8 encoded string. The header names and their values are included when calculating the size.
x-amz-storage-class Object storage class.

Possible values:

- COLD for uploading an object to the cold storage.
- STANDARD for uploading an object to the standard storage.

If no header is specified, the object is saved to the standard storage.



A response can only contain common response headers.

Response codes

For a list of possible responses, see Responses.

A successful response contains additional data in XML format with the schema described below.

Data schema

Tag Description
InitiateMultipartUploadResult Response root tag.

Path: /InitiateMultipartUploadResult.
Bucket Name of the bucket the object is uploaded to.

Path: /InitiateMultipartUploadResult/Bucket.
Key Key associated with the object after the upload is complete.

Path: /InitiateMultipartUploadResult/Key.
UploadId Upload ID.

All subsequent upload operations should pass this ID to Object Storage.

Path: /InitiateMultipartUploadResult/UploadId.