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 Name of the bucket.
key Object key. The object will be saved in Object Storage with the specified name.

Query parameters

Parameter Description
uploads Flag indicating a multipart upload operation.


Use the necessary common request headers in requests.

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

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

Object Storage treats all headers starting with x-amz-meta- as user-defined. It doesn't process these headers, but saves them in the original format.

The total size of user-defined headers must 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:
- STANDARD for uploading an object to standard storage.
- COLD, STANDARD_IA, and NEARLINE for uploading an object to cold storage.

If the header is omitted, the object is saved to the storage specified in the bucket settings.

By using the headers listed below, you can set the ACL for an object to be uploaded.

Heading Description
x-amz-acl Sets a predefined ACL for an object.
x-amz-grant-read Grants the access grantee object read permission.
x-amz-grant-read-acp Grants the access grantee object ACL read permission.
x-amz-grant-write-acp Grants the access grantee object ACL write permission.
x-amz-grant-full-control Grants the access grantee the following permissions: READ, WRITE, READ_ACP, and WRITE_ACP for an object.

The value for a x-amz-grant-* header is a comma-separated list of access grantees. Each access grantee is identified in a structure like: <access grantee type>:<access grantee ID>. Object Storage supports the following types of access grantees:

  • id — access grantee — Yandex.Cloud user.
  • uri — access grantee — system group.


x-amz-grant-read: uri=""



Responses can only contain common response headers.

Response codes

For the 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 must pass this ID to Object Storage.

Path: /InitiateMultipartUploadResult/UploadId.