# Develop enhanced fan-out consumers with dedicated throughput
<a name="enhanced-consumers"></a>

In Amazon Kinesis Data Streams, you can build consumers that use a feature called *enhanced fan-out*. This feature lets consumers receive records from a stream with throughput of up to 2 MB of data per second per shard. This throughput is dedicated, which means that consumers that use enhanced fan-out don't have to contend with other consumers that are receiving data from the stream. Kinesis Data Streams pushes data records from the stream to consumers that use enhanced fan-out. Therefore, these consumers don't need to poll for data.

**Important**  
With On-demand Advantage mode, you can register up to 50 consumers per stream to use enhanced fan-out. With On-demand Standard and Provisioned streams, you can register up to 20 consumers per stream to use enhanced fan-out. 

The following diagram shows the enhanced fan-out architecture. If you use version 2.0 or later of the Amazon Kinesis Client Library (KCL) to build a consumer, the KCL sets up the consumer to use enhanced fan-out to receive data from all the shards of the stream. If you use the API to build a consumer that uses enhanced fan-out, then you can subscribe to individual shards.

![\[Workflow diagram showing enhanced fan-out architecture with two shards and two consumers. Each of the two consumers is using enhanced fan-out to receive data from both shards of the stream.\]](http://docs.aws.amazon.com/streams/latest/dev/images/enhanced_fan-out.png)


The diagram shows the following: 
+ A stream with two shards.
+ Two consumers that are using enhanced fan-out to receive data from the stream: Consumer X and Consumer Y. Each of the two consumers is subscribed to all of the shards and all of the records of the stream. If you use version 2.0 or later of the KCL to build a consumer, the KCL automatically subscribes that consumer to all the shards of the stream. On the other hand, if you use the API to build a consumer, you can subscribe to individual shards. 
+ Arrows representing the enhanced fan-out pipes that the consumers use to receive data from the stream. An enhanced fan-out pipe provides up to 2 MB/sec of data per shard, independently of any other pipes or of the total number of consumers.

**Topics**
+ [

## Differences between shared throughput consumer and enhanced fan-out consumer
](#enhanced-consumers-differences)
+ [

## Regions supported for up to 50 enhanced fan-out consumers (On-demand Advantage only)
](#supported-regions)
+ [

# Manage enhanced fan-out consumers with the AWS CLI or APIs
](building-enhanced-consumers-console.md)

## Differences between shared throughput consumer and enhanced fan-out consumer
<a name="enhanced-consumers-differences"></a>

The following table compares default shared-throughput consumers to enhanced fan-out consumers. Message propagation delay is defined as the time taken in milliseconds for a payload sent using the payload-dispatching APIs (like `PutRecord` and `PutRecords`) to reach the consumer application through the payload-consuming APIs (like `GetRecords` and `SubscribeToShard`).


**This table compares shared-throughput consumers to enhanced fan-out consumers**  

| Characteristics | Shared throughput consumers without enhanced fan-out | Enhanced fan-out consumers | 
| --- | --- | --- | 
| Read throughput |  Fixed at a total of 2 MB/sec per shard. If there are multiple consumers reading from the same shard, they all share this throughput. The sum of the throughputs they receive from the shard doesn't exceed 2 MB/sec.  |  Scales as consumers register to use enhanced fan-out. Each consumer registered to use enhanced fan-out receives its own read throughput per shard, up to 2 MB/sec, independently of other consumers.  | 
| Message propagation delay |  An average of around 200 ms if you have one consumer reading from the stream. This average goes up to around 1000 ms if you have five consumers.  |  Typically an average of 70 ms whether you have one consumer or five consumers.  | 
| Cost | Not applicable |  There is a data retrieval cost and a consumer-shard hour cost. For more information, see [Amazon Kinesis Data Streams Pricing](https://aws.amazon.com/kinesis/data-streams/pricing/?nc=sn&loc=3).  | 
| Record delivery model |  Pull model over HTTP using GetRecords.  |  Kinesis Data Streams pushes the records to you over HTTP/2 using SubscribeToShard.  | 

## Regions supported for up to 50 enhanced fan-out consumers (On-demand Advantage only)
<a name="supported-regions"></a>

 Support for up to 50 enhanced fan-out consumers in On-demand Advantage mode is available only in the following AWS Regions:


| AWS Region | Region Name | 
| --- | --- | 
|  eu-north-1 | Europe (Stockholm) | 
|  me-south-1 | Middle East (Bahrain) | 
|  ap-south-1 | Asia Pacific (Mumbai) | 
|  eu-west-3 | Europe (Paris) | 
|  ap-southeast-3 | Asia Pacific (Jakarta) | 
|  us-east-2 | US East (Ohio) | 
|  af-south-1 | Africa (Cape Town) | 
|  eu-west-1 | Europe (Ireland) | 
|  me-central-1 | Middle East (UAE) | 
|  eu-central-1 | Europe (Frankfurt) | 
|  sa-east-1 | South America (São Paulo) | 
|  ap-east-1 | Asia Pacific (Hong Kong) | 
|  ap-south-2 | Asia Pacific (Hyderabad) | 
|  us-east-1 | US East (N. Virginia) | 
|  ap-northeast-2 | Asia Pacific (Seoul) | 
|  ap-northeast-3 | Asia Pacific (Osaka) | 
|  eu-west-2 | Europe (London) | 
|  ap-southeast-4 | Asia Pacific (Melbourne) | 
|  ap-northeast-1 | Asia Pacific (Tokyo) | 
|  us-west-2 | US West (Oregon) | 
|  us-west-1 | US West (N. California) | 
|  ap-southeast-1 | Asia Pacific (Singapore) | 
|  ap-southeast-2 | Asia Pacific (Sydney) | 
|  il-central-1 | Israel (Tel Aviv) | 
|  ca-central-1 | Canada (Central) | 
|  ca-west-1 | Canada West (Calgary) | 
|  eu-south-2 | Europe (Spain) | 
|  cn-northwest-1 | China (Ningxia) | 
|  eu-central-2 | Europe (Zurich) | 
| us-gov-east-1 | AWS GovCloud (US-East) | 
| us-gov-west-1 | AWS GovCloud (US-West) | 

# Manage enhanced fan-out consumers with the AWS CLI or APIs
<a name="building-enhanced-consumers-console"></a>

Consumers that use *enhanced fan-out* in Amazon Kinesis Data Streams can receive records from a data stream with dedicated throughput of up to 2 MB of data per second per shard. For more information, see [Develop enhanced fan-out consumers with dedicated throughput](enhanced-consumers.md).

You can use AWS CLI or Kinesis Data Streams APIs to register, describe, list, and deregister a consumer that uses enhanced fan-out in Kinesis Data Streams.

## Manage consumers using the AWS CLI
<a name="manage-consumers-cli"></a>

You can register, describe, list, and deregister enhanced fan-out consumers using the AWS CLI. For examples, see the following documentation.

[register-stream-consumer](https://awscli.amazonaws.com/v2/documentation/api/latest/reference/kinesis/register-stream-consumer.html)  
Registers a consumer for a Kinesis data stream. You can apply tags while registering the consumer. 

[describe-stream-consumer](https://awscli.amazonaws.com/v2/documentation/api/latest/reference/kinesis/describe-stream-consumer.html)  
Gets the description of a registered consumer with either consumer ARN or consumer name and stream ARN combination.

[list-stream-consumers](https://awscli.amazonaws.com/v2/documentation/api/latest/reference/kinesis/list-stream-consumers.html)  
Lists the consumers registered to receive data from a stream using enhanced fan-out.

[deregister-stream-consumer](https://awscli.amazonaws.com/v2/documentation/api/latest/reference/kinesis/deregister-stream-consumer.html)  
Deregister a consumer with either consumer ARN or consumer name and stream ARN combination.

## Manage consumers using the Kinesis Data Streams APIs
<a name="manage-consumers-api"></a>

You can register, describe, list, and deregister enhanced fan-out consumers using the Kinesis Data Streams APIs. For examples, see the following documentation.

[RegisterStreamConsumer](https://docs.aws.amazon.com/kinesis/latest/APIReference/API_RegisterStreamConsumer.html)  
Registers a consumer for a Kinesis data stream with tags. You can apply tags while registering the consumer.

[DescribeStreamConsumer](https://docs.aws.amazon.com/kinesis/latest/APIReference/API_DescribeStreamConsumer.html)  
Gets the description of a registered consumer with either consumer ARN or consumer name and stream ARN combination.

[ListStreamConsumers](https://docs.aws.amazon.com/kinesis/latest/APIReference/API_ListStreamConsumers.html)  
Lists the consumers registered to receive data from a stream using enhanced fan-out.

[DeregisterStreamConsumer](https://docs.aws.amazon.com/kinesis/latest/APIReference/API_DeregisterStreamConsumer.html)  
Deregister a consumer with either consumer ARN or consumer name and stream ARN combination.

## Tagging consumers
<a name="tag-consumers"></a>

You can assign your own metadata to streams and enhanced fan-out consumers you create in Kinesis Data Streams in the form of tags. You can use tags to categorize and track costs of your consumers. You can also control access to consumers using tags with [attribute-based access control (ABAC)](https://docs.aws.amazon.com/IAM/latest/UserGuide/introduction_attribute-based-access-control.html). For more information, see [Tag your Amazon Kinesis Data Streams resources](tagging.md).