What types of integration exist? How to connect two systems?

There are several types of system integration:

• Point-to-Point Integration: direct connection between two systems. Fast, but poorly scalable.
• ESB (Enterprise Service Bus) Integration: a centralized mediator that routes and transforms messages.
• API Integration: systems interact through open APIs (REST, SOAP).
• Message Queues: asynchronous exchange via message brokers (Kafka, RabbitMQ).
• File Exchange: data exchange through files (CSV, XML), often in batch mode.

To "connect" two systems, you need to:

1. Define the data exchange format and protocol.
2. Ensure data transformation if formats differ.
3. Configure the delivery mechanism (synchronous or asynchronous).
4. Ensure error handling and monitoring.

For example, CRM and ERP integration can be implemented via REST API with JSON, where CRM sends customer data, and ERP processes it.