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.
Ingress Connectors act as message entry points to Integration Flows of an Ultra Project. An Ultra Project can consist of one or more Ingress Connectors where an Integration Flow typically starts with a one. An Ingress 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 Ingress Connectors based on their underlying transport protocol.
The first type is In-Out type Ingress Connectors that not only accept messages from external systems, but also send back a response in return. Ingress connectors such as HTTP, AS2 and FIX are of this type.
The second type is In-Only type Ingress Connectors that only accept messages from external systems, but do not send back any response in return. Ingress connectors such as SFTP, JMS, FILE, Database and AMQP are of this type.
You can check the list of Ingress 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.