Put Blob

The Put Blob operation creates a new block blob or updates the content of an existing block blob.

Updating an existing block blob overwrites any existing metadata on the blob. Partial updates are not supported with Put Blob; the content of the existing blob is overwritten with the content of the new blob. To perform a partial update of the content of a block blob, use the Put Block List operation.


Construct the Put Blob request as follows. HTTPS is recommended. Replace myaccount with the name of your storage account, and example.com with your endpoint’s domain name or IP address.

Method Request URI HTTP Version
PUT https://myaccount.blob.example.com/mycontainer/myblob HTTP/1.1

URI Parameters

The following additional parameters may be specified on the request URI.

Parameter Description
timeout Optional. The timeout parameter is expressed in seconds. For more information, see Setting Timeouts for Blob Service Operations.

Request Headers (All Blob Types)

The following table describes required and optional request headers for all blob types.

Request header Description
Authorization Required. Specifies the authorization scheme, account name, and signature. For more information, see Authorize requests to Azure Storage.
Date or x-ms-date Required. Specifies the Coordinated Universal Time (UTC) for the request. For more information, see Authorize requests to Azure Storage.
x-ms-version Required for all authorized requests. Specifies the version of the operation to use for this request. For more information, see Versioning for the Azure Storage Services.
Content-Length Required. The length of the request.
Content-Type Optional. The MIME content type of the blob. The default type is application/octet-stream.
Content-Encoding Optional. Specifies which content encodings have been applied to the blob. This value is returned to the client when the Get Blob operation is performed on the blob resource. The client can use this value when returned to decode the blob content.
Content-Language Optional. Specifies the natural languages used by this resource.
Content-MD5 Optional. An MD5 hash of the blob content. This hash is used to verify the integrity of the blob during transport. When this header is specified, the storage service checks the hash that has arrived with the one that was sent. If the two hashes do not match, the operation will fail with error code 400 (Bad Request). When omitted, the Blob service generates an MD5 hash. Results from Get Blob, Get Blob Properties, and List Blobs include the MD5 hash.
Cache-Control Optional. The Blob service stores this value but does not use or modify it.
x-ms-blob-content-type Optional. Sets the blob’s content type.
x-ms-blob-content-encoding Optional. Sets the blob’s content encoding.
x-ms-blob-content-language Optional. Sets the blob’s content language.
x-ms-blob-content-md5 Optional. Sets the blob’s MD5 hash.
x-ms-blob-cache-control Optional. Sets the blob’s cache control.
x-ms-blob-type: BlockBlob

Required. Specifies the type of blob to create: block blob, page blob, or append blob.


Zenko version 1.2.1 supports block blobs only. Set this value to BlockBlob.

x-ms-meta-name:value Optional. Name-value pairs associated with the blob as metadata. Metadata names must adhere to the naming rules for C# identifiers.
x-ms-lease-id Not applicable (Zenko 1.2.1 does not support leasing).
x-ms-blob-content-disposition Optional. Sets the blob’s Content-Disposition header. The Content-Disposition response header field conveys additional information about how to process the response payload, and also can be used to attach additional metadata. For example, if set to attachment, it indicates that the user-agent should not display the response, but instead show a Save As dialog with a filename other than the blob name specified. The response from the Get Blob and Get Blob Properties operations includes the content-disposition header.
Origin Optional. Specifies the origin from which the request is issued. The presence of this header results in cross-origin resource sharing headers on the response. See Cross-Origin Resource Sharing (CORS) support for Azure Storage for details.
x-ms-client-request-id Optional. Provides a client-generated, opaque value with a 1 KB character limit that is recorded in the analytics logs when storage analytics logging is enabled. Using this header is highly recommended for correlating client-side activities with requests received by the server. For more information, see Azure Storage Analytics Logging and Windows Azure Logging: Using Logs to Track Storage Requests.
x-ms-access-tier Not applicable (Zenko version 1.2.1 does not support tiering).

This operation also supports the use of conditional headers to write the blob only if a specified condition is met. For more information, see Specifying conditional headers for Blob service operations.

Request Body

The request body contains the content of the blob.

Sample Request

The following example shows a request to create a block blob:

Request Syntax:
PUT https://myaccount.blob.example.com/mycontainer/myblockblob HTTP/1.1

Request Headers:
x-ms-version: 2015-02-21
x-ms-date: <date>
Content-Type: text/plain; charset=UTF-8
x-ms-blob-content-disposition: attachment; filename="fname.ext"
x-ms-blob-type: BlockBlob
x-ms-meta-m1: v1
x-ms-meta-m2: v2
Authorization: SharedKey myaccount:YhuFJjN4fAR8/AmBrqBz7MG2uFinQ4rkh4dscbj598g=
Content-Length: 11

Request Body:
hello world


The response includes an HTTP status code and a set of response headers.

Status Codes

A successful operation returns status code 201 (Created).

For information about status codes, see Status and Error Codes.

Response Headers

The response for this operation includes the following headers. The response can also include additional standard HTTP headers. All standard headers conform to the HTTP/1.1 protocol specification.

Response Header Description
ETag The ETag contains a value that the client can use to perform conditional PUT operations by using the If-Match request header. The ETag value will be in quotes.
Last-Modified The date/time that the blob was last modified. The date format follows RFC 1123. For more information, see Representation of date/time values in headers. Any write operation on the blob (including updates on the blob’s metadata or properties) changes the blob’s last-modified time.
Content-MD5 This header is returned for a block blob so the client can check the integrity of message content. The Content-MD5 value returned is computed by the Blob service. This header is returned even when the request does not include Content-MD5 or x-ms-blob-content-md5 headers.
x-ms-request-id This header uniquely identifies the request that was made and can be used for troubleshooting the request. For more information, see Troubleshooting API operations.
x-ms-version Indicates the version of the Blob service used to execute the request.
Date A UTC date/time value generated by the service that indicates the time at which the response was initiated.
Access-Control-Allow-Origin Returned if the request includes an Origin header and CORS is enabled with a matching rule. This header returns the value of the origin request header in case of a match.
Access-Control-Expose-Headers Returned if the request includes an Origin header and CORS is enabled with a matching rule. Returns the list of response headers that are to be exposed to the client or issuer of the request.
Access-Control-Allow-Credentials Returned if the request includes an Origin header and CORS is enabled with a matching rule that does not allow all origins. This header will be set to true.
x-ms-request-server-encrypted: true/false The value of this header is set to true if the contents of the request are successfully encrypted using the specified algorithm, and false otherwise.
x-ms-encryption-key-sha256 This header is returned if the request used a customer-provided encryption key, so the client can ensure the contents of the request are successfully encrypted using the provided key.

Response Body


Sample Response

Response Status:
HTTP/1.1 201 Created

Response Headers:
Transfer-Encoding: chunked
Content-MD5: sQqNsWTgdUEFt6mb5y4/5Q==
x-ms-content-crc64: 77uWZTolTHU
Date: <date>
ETag: "0x8CB171BA9E94B0B"
Last-Modified: <date>
Access-Control-Allow-Origin: http://contoso.com
Access-Control-Expose-Headers: Content-MD5
Access-Control-Allow-Credentials: True
Server: Windows-Azure-Blob/1.0 Microsoft-HTTPAPI/2.0


This operation can be called by the account owner and by any client with a shared access signature that has permission to write to this blob or its container.


When you create a blob, you must specify the block blob type using the x-ms-blob-type header. Blobserver only supports the block blob type.

The maximum size for a block blob created via Put Blob is 256 MB. If your blob is larger than 256 MB, you must upload it as a set of blocks. For more information, see Put Block and Put Block List. Calling Put Blob is unnecessary if you upload the blob as a set of blocks.

If you attempt to upload a block blob that is larger than 256 MB, the service returns status code 413 (Request Entity Too Large). The Blob service also returns additional information about the error in the response, including the maximum blob size permitted in bytes.

A blob has custom properties (set via headers) that you can use to store values associated with standard HTTP headers. These values can subsequently be read by calling Get Blob Properties, or modified by calling Set Blob Properties. The custom property headers and corresponding standard HTTP header are listed in the following table:

HTTP Header Custom Blob Property Header
Content-Type x-ms-blob-content-type
Content-Encoding x-ms-blob-content-encoding
Content-Language x-ms-blob-content-language
Content-MD5 x-ms-blob-content-md5
Cache-Control x-ms-blob-cache-control

The semantics for setting persisting these property values with the blob as follows:

  • If the client specifies a custom property header, as indicated by the x-ms-blob prefix, this value is stored with the blob.
  • If the client specifies a standard HTTP header, but not the custom property header, the value is stored in the corresponding custom property associated with the blob, and is returned by a call to Get Blob Properties. For example, if the client sets the Content-Type header on the request, that value is stored in the blob’s x-ms-blob-content-type property.
  • If the client sets both the standard HTTP header and the corresponding property header on the same request, the PUT request uses the value provided for the standard HTTP header, but the value specified for the custom property header is persisted with the blob and returned by subsequent GET requests.

A Put Blob operation is permitted 10 minutes per MB to complete. If the operation takes longer than 10 minutes per MB on average, the operation times out.