Domain Sharding: This technique involves spreading your assets across multiple subdomains of your main domain (e.g., assets1 example com, assets2.example com). Be cautious with domain sharding, as it can also increase DNS lookup times if not managed properly.

During contests which have a lot of traffic, I have seen codeforces suggesting to use different domains, sometimes it even redirects to different domains which are not codeforces.com

Just curious, why is Domain sharding used in codeforces?

My simple guess is maybe they don't want to vertically scale their servers and hence they are horizontally scaling it by distributing the load to totally different domains? But it could also be because they want to get over the browser limitations of number of simultaneous connections to a particular webiste? I am just curious.

Thanks & Regards