What is the conceptual difference between synchronous and asynchronous integration?

Synchronous and asynchronous integration differ in the way systems interact and handle requests.

• Synchronous integration: the client sends a request and waits for a response from the server in real time. This means the process is blocked until the result is received. This approach is convenient when immediate feedback is needed, for example, when making API requests.

• Asynchronous integration: the client sends a request and does not wait for an immediate response, continuing to work. The response arrives later, usually through a message queue or callback. This increases system resilience and allows processing tasks with delay or in the background.

Example: during order payment, a synchronous call will check the payment immediately, while an asynchronous one can send an event about the order to a queue for subsequent processing and notification.