Website performance is about two things: how fast the page loads, and how fast the code on it runs. Plenty of services will make your website load faster, from minimizers to CDNs, but making it run faster is up to you.
A. Roy, S. Hand, and T. Harris. Proceedings of the 7th ACM SIGPLAN/SIGOPS international conference on Virtual execution environments, page 227--238. ACM, (Mar 9, 2011)
H. Burchell, O. Larose, S. Kaleba, and S. Marr. Proceedings of the 20th ACM SIGPLAN International Conference on Managed Programming Languages and Runtimes, page 1--14. ACM, (October 2023)
Y. Zheng, L. Bulej, and W. Binder. Proceedings of the 2015 ACM SIGPLAN International Conference on Object-Oriented Programming, Systems, Languages, and Applications, page 433--450. ACM, (October 2015)
T. Mytkowicz, A. Diwan, M. Hauswirth, and P. Sweeney. Proceedings of the 31st ACM SIGPLAN Conference on Programming Language Design and Implementation, page 187--197. ACM, (June 2010)
A. Rosà, L. Chen, and W. Binder. Proceedings of the 2016 ACM SIGPLAN International Conference on Generative Programming: Concepts and Experiences, page 36--46. ACM, (2016)