Connectors are used to integrate Project-X Integration Flows with external systems. Project-X is consist of two main types of connectors as Ingress Connectors and Egress Connectors.
Egress Connectors act as message exit points from Integration Flows of an Ultra Project. An Ultra Project can consist of one or more Egress Connectors where an Integration Flow also can have several Egress Connectors. An Egress Connector implements either a basic transport protocol such as HTTP, JMS, SFTP or it can implement a specification of a transport protocol such as AS2 (Applicability Statement 2).
In Project-X, there are mainly two types of Egress Connectors based on their underlying transport protocol.
The first type is Bi-directional Egress Connectors that not only send messages to external systems, but also receive back a response in return and inject it to the response path of the Integration Flow. Egress connectors such as HTTP, AS2 and FIX are of this type.
The second type is Out-Only type Egress Connectors that only send messages to external systems, but do not expect a response. Egress connectors such as SFTP, JMS, FILE, Database and AMQP are of this type.
You can check the list of Egress Connectors that are currently available in Project-X by default from here. Please refer the documentation on connectors for more details and sample use cases of these connectors. Also refer the developer guide on how to write a custom connector.