# ListCollections
<a name="API_ListCollections"></a>

Returns list of collection IDs in your account. If the result is truncated, the response also provides a `NextToken` that you can use in the subsequent request to fetch the next set of collection IDs.

For an example, see [Listing collections](https://docs.aws.amazon.com/rekognition/latest/dg/list-collection-procedure.html).

This operation requires permissions to perform the `rekognition:ListCollections` action.

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

```
{
   "MaxResults": number,
   "NextToken": "string"
}
```

## Request Parameters
<a name="API_ListCollections_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.

 ** [MaxResults](#API_ListCollections_RequestSyntax) **   <a name="rekognition-ListCollections-request-MaxResults"></a>
Maximum number of collection IDs to return.   
Type: Integer  
Valid Range: Minimum value of 0. Maximum value of 4096.  
Required: No

 ** [NextToken](#API_ListCollections_RequestSyntax) **   <a name="rekognition-ListCollections-request-NextToken"></a>
Pagination token from the previous response.  
Type: String  
Length Constraints: Maximum length of 255.  
Required: No

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

```
{
   "CollectionIds": [ "string" ],
   "FaceModelVersions": [ "string" ],
   "NextToken": "string"
}
```

## Response Elements
<a name="API_ListCollections_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.

 ** [CollectionIds](#API_ListCollections_ResponseSyntax) **   <a name="rekognition-ListCollections-response-CollectionIds"></a>
An array of collection IDs.  
Type: Array of strings  
Length Constraints: Minimum length of 1. Maximum length of 255.  
Pattern: `[a-zA-Z0-9_.\-]+` 

 ** [FaceModelVersions](#API_ListCollections_ResponseSyntax) **   <a name="rekognition-ListCollections-response-FaceModelVersions"></a>
Version numbers of the face detection models associated with the collections in the array `CollectionIds`. For example, the value of `FaceModelVersions[2]` is the version number for the face detection model used by the collection in `CollectionId[2]`.  
Type: Array of strings

 ** [NextToken](#API_ListCollections_ResponseSyntax) **   <a name="rekognition-ListCollections-response-NextToken"></a>
If the result is truncated, the response provides a `NextToken` that you can use in the subsequent request to fetch the next set of collection IDs.  
Type: String  
Length Constraints: Maximum length of 255.

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

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

 ** AccessDeniedException **   
You are not authorized to perform the action.  
HTTP Status Code: 400

 ** InternalServerError **   
Amazon Rekognition experienced a service issue. Try your call again.  
HTTP Status Code: 500

 ** InvalidPaginationTokenException **   
Pagination token in the request is not valid.  
HTTP Status Code: 400

 ** InvalidParameterException **   
Input parameter violated a constraint. Validate your parameter before calling the API operation again.  
HTTP Status Code: 400

 ** ProvisionedThroughputExceededException **   
The number of requests exceeded your throughput limit. If you want to increase this limit, contact Amazon Rekognition.  
HTTP Status Code: 400

 ** ResourceNotFoundException **   
The resource specified in the request cannot be found.  
HTTP Status Code: 400

 ** ThrottlingException **   
Amazon Rekognition is temporarily unable to process the request. Try your call again.  
HTTP Status Code: 500

## See Also
<a name="API_ListCollections_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/rekognition-2016-06-27/ListCollections) 
+  [AWS SDK for .NET V4](https://docs.aws.amazon.com/goto/DotNetSDKV4/rekognition-2016-06-27/ListCollections) 
+  [AWS SDK for C\$1\$1](https://docs.aws.amazon.com/goto/SdkForCpp/rekognition-2016-06-27/ListCollections) 
+  [AWS SDK for Go v2](https://docs.aws.amazon.com/goto/SdkForGoV2/rekognition-2016-06-27/ListCollections) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/rekognition-2016-06-27/ListCollections) 
+  [AWS SDK for JavaScript V3](https://docs.aws.amazon.com/goto/SdkForJavaScriptV3/rekognition-2016-06-27/ListCollections) 
+  [AWS SDK for Kotlin](https://docs.aws.amazon.com/goto/SdkForKotlin/rekognition-2016-06-27/ListCollections) 
+  [AWS SDK for PHP V3](https://docs.aws.amazon.com/goto/SdkForPHPV3/rekognition-2016-06-27/ListCollections) 
+  [AWS SDK for Python](https://docs.aws.amazon.com/goto/boto3/rekognition-2016-06-27/ListCollections) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/rekognition-2016-06-27/ListCollections)