Product Strategy

Speed as Strategy: Why Performance is a Product Manager’s Best Friend

Taninwat Kaewpankan
2025-12-03
5 min read

In economics, we study opportunity cost. In frontend development, we study latency. They are the same thing.

Every millisecond a user waits for your app to load is a "tax" on their attention span. If that tax gets too high, they churn. As a Product Engineer, I don't just look at Lighthouse scores as vanity metrics—I look at them as revenue indicators.

The "100ms" Rule

Amazon found that every 100ms of latency cost them 1% in sales. Google found that an extra 0.5 seconds in search page generation dropped traffic by 20%.

When I build a feature, I ask three questions:

  1. Does this spark joy? (UX)
  2. Does this solve a problem? (Product)
  3. Does the "weight" of this feature justify the "wait" for the user? (Performance Economics)

Why I Moved to Next.js (The Business Case)

My decision to migrate this portfolio from a client-side SPA (Vite) to Next.js wasn't just about using the latest tech. It was a calculated move to improve First Contentful Paint (FCP).

  • Client-Side Rendering (CSR): The browser downloads a blank page, then a huge JS bundle, then renders. The user stares at a white screen. Result: High bounce rate.
  • Server-Side Rendering (SSR): The server sends a fully formed HTML page instantly. Result: Immediate perceived value.

Optimizing for the "Next" User

Technical debt isn't just bad code; it's a bad product strategy.

By obsessing over Core Web Vitals—optimizing images to WebP, lazy-loading heavy components, and code-splitting routes—I am respecting the user's time.

In a crowded market, you don't always win by having the most features. Sometimes, you win simply by being the fastest to solve the problem.