HeadBucket - Amazon Simple Storage Service
Archived: 2026-04-06 01:27:36 UTC
You can use this operation to determine if a bucket exists and if you have permission to access it. The action
returns a 200 OK HTTP status code if the bucket exists and you have permission to access it. You can make a
HeadBucket call on any bucket name to any Region in the partition, and regardless of the permissions on the
bucket, you will receive a response header with the correct bucket location so that you can then make a proper,
signed request to the appropriate Regional endpoint.
Note
If the bucket doesn't exist or you don't have permission to access it, the HEAD request returns a generic 400 Bad
Request , 403 Forbidden , or 404 Not Found HTTP status code. A message body isn't included, so you can't
determine the exception beyond these HTTP response codes.
Authentication and authorization
General purpose buckets - Request to public buckets that grant the s3:ListBucket permission publicly do
not need to be signed. All other HeadBucket requests must be authenticated and signed by using IAM
credentials (access key ID and secret access key for the IAM identities). All headers with the x-amz-prefix, including x-amz-copy-source , must be signed. For more information, see REST Authentication.
Directory buckets - You must use IAM credentials to authenticate and authorize your access to the
HeadBucket API operation, instead of using the temporary security credentials through the
CreateSession API operation.
AWS CLI or SDKs handles authentication and authorization on your behalf.
Permissions
General purpose bucket permissions - To use this operation, you must have permissions to
perform the s3:ListBucket action. The bucket owner has this permission by default and can grant
this permission to others. For more information about permissions, see Managing access
permissions to your Amazon S3 resources in the Amazon S3 User Guide.
Directory bucket permissions - You must have the s3express:CreateSession permission in the
Action element of a policy. If no session mode is specified, the session will be created with the
maximum allowable privilege, attempting ReadWrite first, then ReadOnly if ReadWrite is not
permitted. If you want to explicitly restrict the access to be read-only, you can set the
s3express:SessionMode condition key to ReadOnly on the bucket.
For more information about example bucket policies, see Example bucket policies for S3 Express
One Zone and AWS Identity and Access Management (IAM) identity-based policies for S3 Express
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One Zone in the Amazon S3 User Guide.
HTTP Host header syntax
Directory buckets - The HTTP Host header syntax is Bucket-name.s3express-zone-id.region-code.amazonaws.com .
Important
You must URL encode any signed header values that contain spaces. For example, if your header value is my
file.txt , containing two spaces after my , you must URL encode this value to my%20%20file.txt .
Request Syntax
HEAD / HTTP/1.1
Host: Bucket .s3.amazonaws.com
x-amz-expected-bucket-owner: ExpectedBucketOwner
URI Request Parameters
The request uses the following URI parameters.
Bucket
The bucket name.
Directory buckets - When you use this operation with a directory bucket, you must use virtual-hosted-style requests in the format Bucket-name.s3express-zone-id.region-code.amazonaws.com . Path-style
requests are not supported. Directory bucket names must be unique in the chosen Zone (Availability Zone
or Local Zone). Bucket names must follow the format bucket-base-name--zone-id--x-s3 (for example,
amzn-s3-demo-bucket--usw2-az1--x-s3 ). For information about bucket naming restrictions, see Directory
bucket naming rules in the Amazon S3 User Guide.
Access points - When you use this action with an access point for general purpose buckets, you must
provide the alias of the access point in place of the bucket name or specify the access point ARN. When
you use this action with an access point for directory buckets, you must provide the access point name in
place of the bucket name. When using the access point ARN, you must direct requests to the access point
hostname. The access point hostname takes the form AccessPointName-AccountId.s3-
accesspoint.Region.amazonaws.com. When using this action with an access point through the AWS SDKs,
you provide the access point ARN in place of the bucket name. For more information about access point
ARNs, see Using access points in the Amazon S3 User Guide.
Object Lambda access points - When you use this API operation with an Object Lambda access point,
provide the alias of the Object Lambda access point in place of the bucket name. If the Object Lambda
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access point alias in a request is not valid, the error code InvalidAccessPointAliasError is returned. For
more information about InvalidAccessPointAliasError , see List of Error Codes.
Note
Object Lambda access points are not supported by directory buckets.
S3 on Outposts - When you use this action with S3 on Outposts, you must direct requests to the S3 on
Outposts hostname. The S3 on Outposts hostname takes the form AccessPointName-AccountId.outpostID.s3-outposts.Region.amazonaws.com . When you use this action with S3 on Outposts,
the destination bucket must be the Outposts access point ARN or the access point alias. For more
information about S3 on Outposts, see What is S3 on Outposts? in the Amazon S3 User Guide.
Required: Yes
x-amz-expected-bucket-owner
The account ID of the expected bucket owner. If the account ID that you provide does not match the actual
owner of the bucket, the request fails with the HTTP status code 403 Forbidden (access denied).
Request Body
The request does not have a request body.
Response Syntax
HTTP/1.1 200
x-amz-bucket-arn: BucketArn
x-amz-bucket-location-type: BucketLocationType
x-amz-bucket-location-name: BucketLocationName
x-amz-bucket-region: BucketRegion
x-amz-access-point-alias: AccessPointAlias
Response Elements
If the action is successful, the service sends back an HTTP 200 response.
The response returns the following HTTP headers.
x-amz-access-point-alias
Indicates whether the bucket name used in the request is an access point alias.
Note
For directory buckets, the value of this field is false .
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x-amz-bucket-arn
The Amazon Resource Name (ARN) of the S3 bucket. ARNs uniquely identify AWS resources across all of
AWS.
Length Constraints: Minimum length of 1. Maximum length of 128.
Pattern: arn:[^:]+:(s3|s3express):.*
x-amz-bucket-location-name
The name of the location where the bucket will be created.
For directory buckets, the Zone ID of the Availability Zone or the Local Zone where the bucket is created.
An example Zone ID value for an Availability Zone is usw2-az1 .
Note
This functionality is only supported by directory buckets.
x-amz-bucket-location-type
The type of location where the bucket is created.
Note
This functionality is only supported by directory buckets.
Valid Values: AvailabilityZone | LocalZone
x-amz-bucket-region
The Region that the bucket is located.
Length Constraints: Minimum length of 0. Maximum length of 20.
Errors
NoSuchBucket
The specified bucket does not exist.
HTTP Status Code: 404
Examples
Sample Request for general purpose buckets
This example illustrates one usage of HeadBucket.
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HEAD / HTTP/1.1
 Date: Fri, 10 Feb 2012 21:34:55 GMT
 Authorization: authorization string
 Host: myawsbucket.s3.amazonaws.com
 Connection: Keep-Alive
 
Sample responses for general purpose buckets
This example illustrates one usage of HeadBucket.
 HTTP/1.1 200 OK
 x-amz-id-2: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
 x-amz-request-id: 28PG2CEB32F5EE25
 x-amz-bucket-region: us-west-2
 x-amz-access-point-alias: false
 Date: Fri, 10 2012 21:34:56 GMT
 Server: AmazonS3
 
 HTTP/1.1 301 Moved Permanantly
 x-amz-id-2: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
 x-amz-request-id: M8H3G2AJ0V6NQ8AJ
 Date: Tue, 06 May 2025 21:29:41 GMT
 x-amz-bucket-region: us-east-1
 x-amz-access-point-alias: false
 Server: AmazonS3
 
 HTTP/1.1 403 Forbidden
 x-amz-bucket-region: us-east-1
 x-amz-request-id: P6K9QSW8EN5YEPS
 x-amz-id-2: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
 Date: Tue, 06 May 2025 21:24:51 GMT
 Server: AmazonS3
 
Example of anonymous request response
This example illustrates one usage of HeadBucket.
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HTTP/1.1 403 Forbidden
 x-amz-bucket-region: us-east-1
 x-amz-request-id: 7B3WF90PGN6J8F2
 x-amz-id-2: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
 Date: Tue, 06 May 2025 21:55:02
 GMT Server: AmazonS3
 
See Also
For more information about using this API in one of the language-specific AWS SDKs, see the following:
AWS Command Line Interface V2
AWS SDK for .NET V4
AWS SDK for C++
AWS SDK for Go v2
AWS SDK for Java V2
AWS SDK for JavaScript V3
AWS SDK for Kotlin
AWS SDK for PHP V3
AWS SDK for Python
AWS SDK for Ruby V3
Source: https://docs.aws.amazon.com/AmazonS3/latest/API/API_HeadBucket.html
https://docs.aws.amazon.com/AmazonS3/latest/API/API_HeadBucket.html
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