How scaling only cart and checkout on Black Friday cut my infrastructure bill and rewired mobile-first execution for composable platforms

https://super-wiki.win/index.php/Architecture_vs_UX:_What_Metro_Brazil%27s_Research_Reveals_About_Technical_Debt_and_System_Complexity

I learned the hard way. Three failed projects, an inflated cloud bill, and a handful of frantic postmortems taught me that you do not need to scale every piece of your e-commerce stack equally for holiday peaks