ISR vs SSR vs CSR: Performance Lessons from Building a Financial Data App with Next.js 14

When you're serving stock data for 100,000+ companies across 73 exchanges, rendering strategy isn't academic - it's the difference between a fast app and an unusable one. Here's what we learned building a financial data platform with Next.js 14. The Challenge Our app serves fundamentally different types of pages: Stock detail pages (/stock/[ticker]): 100,000+ pages, data changes every 6 hours Screener page (/screener): Highly interactive, user-driven filters Leaderboard (/leaderboard): Changes hourly, consumed by many users Blog posts (/blog/[slug]): Rarely changes, needs SEO Each page type demands a different rendering approach. Our Rendering Matrix Page Strategy Revalidate Why /stock/[ticker] ISR 6 hours 100K pages, data changes daily /leaderboard ISR 1 hour Changes frequently, many readers /blog/[slug] ISR (Sanity CMS) 1 hour SEO-critical, CMS-driven /screener CSR - Highly interactive, user-specific Auth pages CSR - User-specific, no SEO need / (home) SSR + Islands - Mix of static a