What is the difference between synchronous and asynchronous interaction?

Synchronous interaction is when the sender of a request waits for a response from the receiver before continuing work. The process is blocked until the result is received. For example, when calling a function that returns a result immediately.

Asynchronous interaction is when the sender initiates a request and does not wait for an immediate response, continuing to perform other tasks. The response arrives later, and its processing occurs through a callback, event, or promise.

Example:

• Synchronous: the program calls a function that makes a request to the database and waits until the data is returned.
• Asynchronous: the program sends a request to the database and continues working, and when the data is ready, a handler is called to process it.

Asynchrony increases system responsiveness and allows more efficient resource utilization, especially when working with slow operations (network, disk). Synchronous is simpler to understand but can lead to blocking and reduced performance.