Amazon Mechanical Turk
API Reference (API Version 2014-08-15)



The BlockWorker operation allows you to prevent a Worker from working on your HITs. For example, you can block a Worker who is producing poor quality work. You can block up to 100,000 Workers.


BlockWorker prevents a Worker from accepting more of your HITs after you block them. However, BlockWorker does not prevent a Worker from submitting assignments that they accepted before you blocked them.

You need the Worker ID to use this operation. You can get the Worker ID in the assignment data returned by a call to the GetAssignmentsForHIT operation. If the Worker ID is missing or invalid, this operation returns with the failure message "WorkerId is invalid." If the Worker is already blocked, this operation returns successfully.

Request Parameters

The BlockWorker operation accepts parameters common to all operations. Some common parameters are required. See Common Parameters for more information.

The following parameters are specific to the BlockWorker operation:



The name of the operation

Type: String

Valid Values: BlockWorker

Default: None



The ID of the Worker to block.

Type: String

Default: None



A message explaining the reason for blocking the Worker. This parameter enables you to keep track of your Workers. The Worker does not see this message.

Type: String

Default: None


Response Elements

A successful request for the BlockWorker operation returns with no errors. The response includes the elements described in the following table. The operation returns no other data.



Contains a Request element if the Request ResponseGroup is specified.


The following example shows how to use the BlockWorker operation.

Sample Request

The following example blocks a Worker from working on your HITs.
&AWSAccessKeyId=[the Requester's Access Key ID]
&Signature=[signature for this request]
&Timestamp=[your system's local time]

Sample Response

The following is an example response.


To unblock a Worker use the UnblockWorker operation.