PutBucketCors - Amazon Simple Storage Service



This operation is not supported by directory buckets.

Sets the cors configuration for your bucket. If the configuration exists, Amazon S3 replaces it.

To use this operation, you must be allowed to perform the s3:PutBucketCORS action. By default, the bucket owner has this permission and can grant it to others.

You set this configuration on a bucket so that the bucket can service cross-origin requests. For example, you might want to enable a request whose origin is http://www.example.com to access your Amazon S3 bucket at my.example.bucket.com by using the browser's XMLHttpRequest capability.

To enable cross-origin resource sharing (CORS) on a bucket, you add the cors subresource to the bucket. The cors subresource is an XML document in which you configure rules that identify origins and the HTTP methods that can be executed on your bucket. The document is limited to 64 KB in size.

When Amazon S3 receives a cross-origin request (or a pre-flight OPTIONS request) against a bucket, it evaluates the cors configuration on the bucket and uses the first CORSRule rule that matches the incoming browser request to enable a cross-origin request. For a rule to match, the following conditions must be met:

  • The request's Origin header must match AllowedOrigin elements.

  • The request method (for example, GET, PUT, HEAD, and so on) or the Access-Control-Request-Method header in case of a pre-flight OPTIONS request must be one of the AllowedMethod elements.

  • Every header specified in the Access-Control-Request-Headers request header of a pre-flight request must match an AllowedHeader element.

For more information about CORS, go to Enabling Cross-Origin Resource Sharing in the Amazon S3 User Guide.

The following operations are related to PutBucketCors:

Request Syntax

PUT /?cors HTTP/1.1 Host: Bucket.s3.amazonaws.com Content-MD5: ContentMD5 x-amz-sdk-checksum-algorithm: ChecksumAlgorithm x-amz-expected-bucket-owner: ExpectedBucketOwner <?xml version="1.0" encoding="UTF-8"?> <CORSConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/"> <CORSRule> <AllowedHeader>string</AllowedHeader> ... <AllowedMethod>string</AllowedMethod> ... <AllowedOrigin>string</AllowedOrigin> ... <ExposeHeader>string</ExposeHeader> ... <ID>string</ID> <MaxAgeSeconds>integer</MaxAgeSeconds> </CORSRule> ... </CORSConfiguration>

URI Request Parameters

The request uses the following URI parameters.


Specifies the bucket impacted by the corsconfiguration.

Required: Yes


The base64-encoded 128-bit MD5 digest of the data. This header must be used as a message integrity check to verify that the request body was not corrupted in transit. For more information, go to RFC 1864.

For requests made using the AWS Command Line Interface (CLI) or AWS SDKs, this field is calculated automatically.


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).


Indicates the algorithm used to create the checksum for the object when you use the SDK. This header will not provide any additional functionality if you don't use the SDK. When you send this header, there must be a corresponding x-amz-checksum or x-amz-trailer header sent. Otherwise, Amazon S3 fails the request with the HTTP status code 400 Bad Request. For more information, see Checking object integrity in the Amazon S3 User Guide.

If you provide an individual checksum, Amazon S3 ignores any provided ChecksumAlgorithm parameter.

Valid Values: CRC32 | CRC32C | SHA1 | SHA256

Request Body

The request accepts the following data in XML format.


Root level tag for the CORSConfiguration parameters.

Required: Yes


A set of origins and methods (cross-origin access that you want to allow). You can add up to 100 rules to the configuration.

Type: Array of CORSRule data types

Required: Yes

Response Syntax

HTTP/1.1 200

Response Elements

If the action is successful, the service sends back an HTTP 200 response with an empty HTTP body.


Example: CORS configuration on a bucket with two rules

  • The first CORSRule allows cross-origin PUT, POST, and DELETE requests whose origin is http://www.example.com origins. The rule also allows all headers in a pre-flight OPTIONS request through the Access-Control-Request-Headers header. Therefore, in response to any pre-flight OPTIONS request, Amazon S3 will return any requested headers.

  • The second rule allows cross-origin GET requests from all the origins. The '*' wildcard character refers to all origins.

<CORSConfiguration> <CORSRule> <AllowedOrigin>http://www.example.com</AllowedOrigin> <AllowedMethod>PUT</AllowedMethod> <AllowedMethod>POST</AllowedMethod> <AllowedMethod>DELETE</AllowedMethod> <AllowedHeader>*</AllowedHeader> </CORSRule> <CORSRule> <AllowedOrigin>*</AllowedOrigin> <AllowedMethod>GET</AllowedMethod> </CORSRule> </CORSConfiguration>

Example: CORS configuration allows cross-origin PUT and POST requests from http://www.example.com

The cors configuration also allows additional optional configuration parameters as shown in the following cors configuration on a bucket. For example,

In the preceding configuration, CORSRule includes the following additional optional parameters:

  • MaxAgeSeconds—Specifies the time in seconds that the browser will cache an Amazon S3 response to a pre-flight OPTIONS request for the specified resource. In this example, this parameter is 3000 seconds. Caching enables the browsers to avoid sending pre-flight OPTIONS request to Amazon S3 for repeated requests.

  • ExposeHeader—Identifies the response header (in this case x-amz-server-side-encryption) that you want customers to be able to access from their applications (for example, from a JavaScript XMLHttpRequest object).

<CORSConfiguration> <CORSRule> <AllowedOrigin>http://www.example.com</AllowedOrigin> <AllowedMethod>PUT</AllowedMethod> <AllowedMethod>POST</AllowedMethod> <AllowedMethod>DELETE</AllowedMethod> <AllowedHeader>*</AllowedHeader> <MaxAgeSeconds>3000</MaxAgeSeconds> <ExposeHeader>x-amz-server-side-encryption</ExposeHeader> </CORSRule> </CORSConfiguration>

See Also

For more information about using this API in one of the language-specific AWS SDKs, see the following: