Have you tested the backend? Do you have experience?

Yes, I have experience testing the backend. In my projects, I wrote and executed functional and integration tests for REST API, checked the correctness of request handling, data validation, and error processing. I also used automation testing tools such as Postman and JUnit to create regression tests.

For example, to test the API, I wrote tests that sent requests with different parameters and checked the responses for compliance with expected statuses and data structures. This helped identify bugs early and ensure the stability of the backend service.