The sixth and final step to create legible and responsive typography is to test and optimize it for your web design. You should consider the loading speed and efficiency, user experience and satisfaction, and quality and standards of your typography. The loading speed and efficiency may be affected by the size, number, and format of your fonts and images. You can use web font loaders, compression, or caching to reduce the size, number, and format of your fonts and images. The user experience and satisfaction may be affected by the legibility, readability, accessibility, and aesthetics of your typography. You can use surveys, analytics, or heatmaps to collect feedback from users. The quality and standards may be affected by the accuracy, consistency, and compliance of your typography. You can use validators, inspectors, or linters to check errors or violations of your typography. Testing and optimizing your typography will help you improve the performance, usability, and quality of your web page.