Performance is usually framed as an engineering concern that design should stay out of. On commerce platforms, that separation costs money — every additional 100ms of checkout latency measurably increases abandonment.
The highest-impact performance decisions are made in design reviews, not sprint retros: how many form fields are on a checkout screen, whether product imagery is optimised before it's approved, whether a modal is really necessary at that step.
We set performance budgets alongside design specs at the start of commerce engagements — a maximum bundle size, a target time-to-interactive — and treat both as equally non-negotiable acceptance criteria.
The result is a checkout flow that feels fast because it was designed to be fast, not optimised after the fact.