What did you test with automated tests: frontend, backend? What library did you use to interact with REST API?

In automated tests, both frontend and backend are usually checked:

• Frontend: UI tests, testing user interaction with the interface, display correctness, form validation.
• Backend: testing REST API, checking business logic, response accuracy, error handling.

Libraries often used for interacting with REST API include:

• Axios — a popular library for HTTP requests in JavaScript/TypeScript.
• Supertest — for testing HTTP servers in Node.js.
• RestAssured — for Java projects.

The choice depends on the project stack, but Axios and Supertest are among the most common for frontend and Node.js tests, respectively.