Functionality (testing all functions, links, forms, scripts...) User experience (testing design, layout, understanding of the content, general accessibility...) Compatibility (Chrome, Firefox, Safari, Windows, macOS, Linux, desktop computers, tablets, smartphones...) Load testing (performance testing when the site is used by a large number of people, response speed, application stability...) Security (testing for possible security vulnerabilities - users' personal data must be safe from external attacks...) Performance after the update (check that the new updates have not negatively affected the functioning of the application)