# Event enrichment in Amazon EventBridge Pipes
Enrichment

With the enrichment step of EventBridge Pipes, you can enhance the data from the source before sending it to the target. For example, you might receive *Ticket created* events that don’t include the full ticket data. Using enrichment, you can have a Lambda function call the `get-ticket` API for the full ticket details. Pipes can then send that information to a [target](eb-pipes-event-target.md).

You can configure the following enrichments when setting up a pipe in EventBridge:
+ API destination
+ Amazon API Gateway
+ Lambda function
+ Step Functions state machine
**Note**  
EventBridge Pipes only supports [Express workflows](https://docs.aws.amazon.com/step-functions/latest/dg/concepts-standard-vs-express.html) as enrichments.

EventBridge invokes enrichments synchronously because it must wait for a response from the enrichment before invoking the target.

Enrichment responses are limited to a maximum size of 6MB.

You can also transform the data you receive from the source before sending it for enhancement. For more information, see [Amazon EventBridge Pipes input transformation](eb-pipes-input-transformation.md).

## Filtering events using enrichment


EventBridge Pipes passes the enrichment responses directly to the configured target. This includes array responses for targets that support batches. For more information about batch behavior, see [Amazon EventBridge Pipes batching and concurrency](eb-pipes-batching-concurrency.md). You can also use your enrichment as a filter and pass fewer events than were received from the source. If you don’t want to invoke the target, return an empty response, such as `""`, `{}`, or `[]`.

**Note**  
If you want to invoke the target with an empty payload, return an array with empty JSON `[{}]`.

## Invoking enrichments
Invoking enrichments

EventBridge invokes enrichments synchronously (invocation type set to `REQUEST_RESPONSE`) because it must wait for a response from the enrichment before invoking the target.

**Note**  
For Step Functions state machines, EventBridge only supports [Express workflows](https://docs.aws.amazon.com/step-functions/latest/dg/concepts-standard-vs-express.html) as enrichments, because they can be invoked synchronously.