What are synchronous and asynchronous calls?

Synchronous calls are when the calling process waits for the operation to complete and the result to be received before continuing its work. This approach is simple and convenient but can lead to blocking and delays if the operation takes a long time.

Asynchronous calls allow initiating an operation and continuing execution without waiting for its completion. The result is processed later, for example, through a callback, event, or polling. This increases system responsiveness and allows efficient resource utilization.

Example:

• Synchronous call: a database query where the application waits for a response.
• Asynchronous call: sending an email via a message queue, where the application continues working immediately, and the sending occurs in the background.