What methods of integrating two systems are you aware of?

The following main methods of system integration are known:

• API integration — data exchange via REST or SOAP services.
• Messages and queues — using message brokers (e.g., RabbitMQ, Kafka) for asynchronous communication.
• File exchange — transferring data through files (CSV, XML) via FTP or other protocols.
• Databases — shared use or replication of data between databases.
• Middleware and ESB — using a data bus for routing and transforming messages.

The choice of method depends on requirements for speed, reliability, data volume, and system architecture.