AWS SDK Version 3 for .NET
API Reference

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Creates a copy of an object that is already stored in Amazon S3.

You can store individual objects of up to 5 TB in Amazon S3. You create a copy of your object up to 5 GB in size in a single atomic action using this API. However, to copy an object greater than 5 GB, you must use the multipart upload Upload Part - Copy (UploadPartCopy) API. For more information, see Copy Object Using the REST Multipart Upload API.

All copy requests must be authenticated. Additionally, you must have read access to the source object and write access to the destination bucket. For more information, see REST Authentication. Both the Region that you want to copy the object from and the Region that you want to copy the object to must be enabled for your account.

A copy request might return an error when Amazon S3 receives the copy request or while Amazon S3 is copying the files. If the error occurs before the copy action starts, you receive a standard Amazon S3 error. If the error occurs during the copy operation, the error response is embedded in the 200 OK response. This means that a 200 OK response can contain either a success or an error. Design your application to parse the contents of the response and handle it appropriately.

If the copy is successful, you receive a response with information about the copied object.

If the request is an HTTP 1.1 request, the response is chunk encoded. If it were not, it would not contain the content-length, and you would need to read the entire body.

The copy request charge is based on the storage class and Region that you specify for the destination object. For pricing information, see Amazon S3 pricing.

Amazon S3 transfer acceleration does not support cross-Region copies. If you request a cross-Region copy using a transfer acceleration endpoint, you get a 400

error. For more information, see Transfer Acceleration.


When copying an object, you can preserve all metadata (default) or specify new metadata. However, the ACL is not preserved and is set to private for the user making the request. To override the default ACL setting, specify a new ACL when generating a copy request. For more information, see Using ACLs.

To specify whether you want the object metadata copied from the source object or replaced with metadata provided in the request, you can optionally add the x-amz-metadata-directive header. When you grant permissions, you can use the s3:x-amz-metadata-directive condition key to enforce certain metadata behavior when objects are uploaded. For more information, see Specifying Conditions in a Policy in the Amazon S3 User Guide. For a complete list of Amazon S3-specific condition keys, see Actions, Resources, and Condition Keys for Amazon S3.

x-amz-copy-source-if Headers

To only copy an object under certain conditions, such as whether the Etag matches or whether the object was modified before or after a specified date, use the following request parameters:

If both the x-amz-copy-source-if-match and x-amz-copy-source-if-unmodified-since headers are present in the request and evaluate as follows, Amazon S3 returns

and copies the data:

If both the x-amz-copy-source-if-none-match and x-amz-copy-source-if-modified-since headers are present in the request and evaluate as follows, Amazon S3 returns the 412 Precondition Failed response code:

All headers with the x-amz- prefix, including x-amz-copy-source, must be signed.

Server-side encryption

When you perform a CopyObject operation, you can optionally use the appropriate encryption-related headers to encrypt the object using server-side encryption with Amazon Web Services managed encryption keys (SSE-S3 or SSE-KMS) or a customer-provided encryption key. With server-side encryption, Amazon S3 encrypts your data as it writes it to disks in its data centers and decrypts the data when you access it. For more information about server-side encryption, see Using Server-Side Encryption.

If a target object uses SSE-KMS, you can enable an S3 Bucket Key for the object. For more information, see Amazon S3 Bucket Keys in the Amazon S3 User Guide.

Access Control List (ACL)-Specific Request Headers

When copying an object, you can optionally use headers to grant ACL-based permissions. By default, all objects are private. Only the owner has full access control. When adding a new object, you can grant permissions to individual Amazon Web Services accounts or to predefined groups defined by Amazon S3. These permissions are then added to the ACL on the object. For more information, see Access Control List (ACL) Overview and Managing ACLs Using the REST API.

If the bucket that you're copying objects to uses the bucket owner enforced setting for S3 Object Ownership, ACLs are disabled and no longer affect permissions. Buckets that use this setting only accept PUT requests that don't specify an ACL or PUT requests that specify bucket owner full control ACLs, such as the bucket-owner-full-control canned ACL or an equivalent form of this ACL expressed in the XML format.

For more information, see Controlling ownership of objects and disabling ACLs in the Amazon S3 User Guide.

If your bucket uses the bucket owner enforced setting for Object Ownership, all objects written to the bucket by any account will be owned by the bucket owner.


When copying an object, if it has a checksum, that checksum will be copied to the new object by default. When you copy the object over, you may optionally specify a different checksum algorithm to use with the x-amz-checksum-algorithm header.

Storage Class Options

You can use the CopyObject action to change the storage class of an object that is already stored in Amazon S3 using the StorageClass parameter. For more information, see Storage Classes in the Amazon S3 User Guide.


By default, x-amz-copy-source identifies the current version of an object to copy. If the current version is a delete marker, Amazon S3 behaves as if the object was deleted. To copy a different version, use the versionId subresource.

If you enable versioning on the target bucket, Amazon S3 generates a unique version ID for the object being copied. This version ID is different from the version ID of the source object. Amazon S3 returns the version ID of the copied object in the x-amz-version-id response header in the response.

If you do not enable versioning or suspend it on the target bucket, the version ID that Amazon S3 generates is always null.

If the source object's storage class is GLACIER, you must restore a copy of this object before you can use it as a source object for the copy operation. For more information, see RestoreObject.

The following operations are related to CopyObject:

For more information, see Copying Objects.


This is an asynchronous operation using the standard naming convention for .NET 4.5 or higher. For .NET 3.5 the operation is implemented as a pair of methods using the standard naming convention of BeginCopyObject and EndCopyObject.

Namespace: Amazon.S3
Assembly: AWSSDK.S3.dll
Version: 3.x.y.z


public virtual Task<CopyObjectResponse> CopyObjectAsync(
         CopyObjectRequest request,
         CancellationToken cancellationToken
Type: Amazon.S3.Model.CopyObjectRequest

Container for the necessary parameters to execute the CopyObject service method.

Type: System.Threading.CancellationToken

A cancellation token that can be used by other objects or threads to receive notice of cancellation.

Return Value
The response from the CopyObject service method, as returned by S3.

Version Information

.NET Core App:
Supported in: 3.1

.NET Standard:
Supported in: 2.0

.NET Framework:
Supported in: 4.5

See Also