# ListTaskDefinitions
<a name="API_ListTaskDefinitions"></a>

Returns a list of task definitions that are registered to your account. You can filter the results by family name with the `familyPrefix` parameter or by status with the `status` parameter.

## Request Syntax
<a name="API_ListTaskDefinitions_RequestSyntax"></a>

```
{
   "familyPrefix": "string",
   "maxResults": number,
   "nextToken": "string",
   "sort": "string",
   "status": "string"
}
```

## Request Parameters
<a name="API_ListTaskDefinitions_RequestParameters"></a>

For information about the parameters that are common to all actions, see [Common Parameters](CommonParameters.md).

The request accepts the following data in JSON format.

 ** [familyPrefix](#API_ListTaskDefinitions_RequestSyntax) **   <a name="ECS-ListTaskDefinitions-request-familyPrefix"></a>
The full family name to filter the `ListTaskDefinitions` results with. Specifying a `familyPrefix` limits the listed task definitions to task definition revisions that belong to that family.  
Type: String  
Required: No

 ** [maxResults](#API_ListTaskDefinitions_RequestSyntax) **   <a name="ECS-ListTaskDefinitions-request-maxResults"></a>
The maximum number of task definition results that `ListTaskDefinitions` returned in paginated output. When this parameter is used, `ListTaskDefinitions` only returns `maxResults` results in a single page along with a `nextToken` response element. The remaining results of the initial request can be seen by sending another `ListTaskDefinitions` request with the returned `nextToken` value. This value can be between 1 and 100. If this parameter isn't used, then `ListTaskDefinitions` returns up to 100 results and a `nextToken` value if applicable.  
Type: Integer  
Required: No

 ** [nextToken](#API_ListTaskDefinitions_RequestSyntax) **   <a name="ECS-ListTaskDefinitions-request-nextToken"></a>
The `nextToken` value returned from a `ListTaskDefinitions` request indicating that more results are available to fulfill the request and further calls will be needed. If `maxResults` was provided, it is possible the number of results to be fewer than `maxResults`.  
This token should be treated as an opaque identifier that is only used to retrieve the next items in a list and not for other programmatic purposes.
Type: String  
Required: No

 ** [sort](#API_ListTaskDefinitions_RequestSyntax) **   <a name="ECS-ListTaskDefinitions-request-sort"></a>
The order to sort the results in. Valid values are `ASC` and `DESC`. By default, (`ASC`) task definitions are listed lexicographically by family name and in ascending numerical order by revision so that the newest task definitions in a family are listed last. Setting this parameter to `DESC` reverses the sort order on family name and revision. This is so that the newest task definitions in a family are listed first.  
Type: String  
Valid Values: `ASC | DESC`   
Required: No

 ** [status](#API_ListTaskDefinitions_RequestSyntax) **   <a name="ECS-ListTaskDefinitions-request-status"></a>
The task definition status to filter the `ListTaskDefinitions` results with. By default, only `ACTIVE` task definitions are listed. By setting this parameter to `INACTIVE`, you can view task definitions that are `INACTIVE` as long as an active task or service still references them. If you paginate the resulting output, be sure to keep the `status` value constant in each subsequent request.  
Type: String  
Valid Values: `ACTIVE | INACTIVE | DELETE_IN_PROGRESS`   
Required: No

## Response Syntax
<a name="API_ListTaskDefinitions_ResponseSyntax"></a>

```
{
   "nextToken": "string",
   "taskDefinitionArns": [ "string" ]
}
```

## Response Elements
<a name="API_ListTaskDefinitions_ResponseElements"></a>

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

The following data is returned in JSON format by the service.

 ** [nextToken](#API_ListTaskDefinitions_ResponseSyntax) **   <a name="ECS-ListTaskDefinitions-response-nextToken"></a>
The `nextToken` value to include in a future `ListTaskDefinitions` request. When the results of a `ListTaskDefinitions` request exceed `maxResults`, this value can be used to retrieve the next page of results. This value is `null` when there are no more results to return.  
Type: String

 ** [taskDefinitionArns](#API_ListTaskDefinitions_ResponseSyntax) **   <a name="ECS-ListTaskDefinitions-response-taskDefinitionArns"></a>
The list of task definition Amazon Resource Name (ARN) entries for the `ListTaskDefinitions` request.  
Type: Array of strings

## Errors
<a name="API_ListTaskDefinitions_Errors"></a>

For information about the errors that are common to all actions, see [Common Error Types](CommonErrors.md).

 ** ClientException **   
These errors are usually caused by a client action. This client action might be using an action or resource on behalf of a user that doesn't have permissions to use the action or resource. Or, it might be specifying an identifier that isn't valid.    
 ** message **   
 Message that describes the cause of the exception.
HTTP Status Code: 400

 ** InvalidParameterException **   
The specified parameter isn't valid. Review the available parameters for the API request.  
For more information about service event errors, see [Amazon ECS service event messages](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/service-event-messages-list.html).     
 ** message **   
 Message that describes the cause of the exception.
HTTP Status Code: 400

 ** ServerException **   
These errors are usually caused by a server issue.    
 ** message **   
 Message that describes the cause of the exception.
HTTP Status Code: 500

## Examples
<a name="API_ListTaskDefinitions_Examples"></a>

In the following example or examples, the Authorization header contents (`AUTHPARAMS`) must be replaced with an AWS Signature Version 4 signature. For more information, see [Signature Version 4 Signing Process](https://docs.aws.amazon.com/general/latest/gr/signature-version-4.html) in the * AWS General Reference*.

You only need to learn how to sign HTTP requests if you intend to create them manually. When you use the [AWS Command Line Interface](http://aws.amazon.com/cli/) or one of the [AWS SDKs](http://aws.amazon.com/tools/) to make requests to AWS, these tools automatically sign the requests for you, with the access key that you specify when you configure the tools. When you use these tools, you don't have to sign requests yourself.

### Example
<a name="API_ListTaskDefinitions_Example_1"></a>

This example request lists all of the task definitions in the `hello_world` family.

#### Sample Request
<a name="API_ListTaskDefinitions_Example_1_Request"></a>

```
POST / HTTP/1.1
Host: ecs.us-east-1.amazonaws.com
Accept-Encoding: identity
Content-Length: 31
X-Amz-Target: AmazonEC2ContainerServiceV20141113.ListTaskDefinitions
X-Amz-Date: 20150429T192041Z
Content-Type: application/x-amz-json-1.1
Authorization: AUTHPARAMS

{
  "familyPrefix": "hello_world"
}
```

#### Sample Response
<a name="API_ListTaskDefinitions_Example_1_Response"></a>

```
HTTP/1.1 200 OK
Server: Server
Date: Wed, 29 Apr 2015 19:20:41 GMT
Content-Type: application/x-amz-json-1.1
Content-Length: 695
Connection: keep-alive
x-amzn-RequestId: 123a4b56-7c89-01d2-3ef4-example5678f

{
  "taskDefinitionArns": [
    "arn:aws:ecs:us-east-1:012345678910:task-definition/hello_world:1",
    "arn:aws:ecs:us-east-1:012345678910:task-definition/hello_world:2",
    "arn:aws:ecs:us-east-1:012345678910:task-definition/hello_world:3",
    "arn:aws:ecs:us-east-1:012345678910:task-definition/hello_world:4",
    "arn:aws:ecs:us-east-1:012345678910:task-definition/hello_world:5",
    "arn:aws:ecs:us-east-1:012345678910:task-definition/hello_world:6",
    "arn:aws:ecs:us-east-1:012345678910:task-definition/hello_world:7",
    "arn:aws:ecs:us-east-1:012345678910:task-definition/hello_world:8",
    "arn:aws:ecs:us-east-1:012345678910:task-definition/hello_world:9",
    "arn:aws:ecs:us-east-1:012345678910:task-definition/hello_world:10"
  ]
}
```

## See Also
<a name="API_ListTaskDefinitions_SeeAlso"></a>

For more information about using this API in one of the language-specific AWS SDKs, see the following:
+  [AWS Command Line Interface V2](https://docs.aws.amazon.com/goto/cli2/ecs-2014-11-13/ListTaskDefinitions) 
+  [AWS SDK for .NET V4](https://docs.aws.amazon.com/goto/DotNetSDKV4/ecs-2014-11-13/ListTaskDefinitions) 
+  [AWS SDK for C\$1\$1](https://docs.aws.amazon.com/goto/SdkForCpp/ecs-2014-11-13/ListTaskDefinitions) 
+  [AWS SDK for Go v2](https://docs.aws.amazon.com/goto/SdkForGoV2/ecs-2014-11-13/ListTaskDefinitions) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/ecs-2014-11-13/ListTaskDefinitions) 
+  [AWS SDK for JavaScript V3](https://docs.aws.amazon.com/goto/SdkForJavaScriptV3/ecs-2014-11-13/ListTaskDefinitions) 
+  [AWS SDK for Kotlin](https://docs.aws.amazon.com/goto/SdkForKotlin/ecs-2014-11-13/ListTaskDefinitions) 
+  [AWS SDK for PHP V3](https://docs.aws.amazon.com/goto/SdkForPHPV3/ecs-2014-11-13/ListTaskDefinitions) 
+  [AWS SDK for Python](https://docs.aws.amazon.com/goto/boto3/ecs-2014-11-13/ListTaskDefinitions) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/ecs-2014-11-13/ListTaskDefinitions)