Why Next.js 15 Is the Smart Choice for Modern Web Apps

Next.js 15 delivers stable Turbopack Dev for dramatic developer performance gains. Across large apps, startups have reported:

• 🚀 ~76% faster local server startup

• ⚡ ~96% quicker hot module refresh

• 🧱 ~46% faster initial route compilation (without caching)

Plus, Turbopack for production builds is now in alpha (as of Next.js 15.3), promising even more speed

Next.js 15 embraces the cutting edge—App Router ships with React 19 RC, while the Pages Router retains React 18 compatibility. That means:

• Early access to React 19 features (hooks like useActionStat )

• Smooth transitions: keep your legacy Pages routes on React 18 while the App Router rides the future

• Key APIs (cookies(), headers(), searchParams) are now async by default, optimizing SSR pipelines—and codemods make upgrading easy.
• Caching behavior has been revised: GET routes and client navigation are uncached by default, putting data freshness over stale content. Opt into caching via config

• The Static Route Indicator in dev mode helps you spot which pages are static vs. dynamic
• The instrumentation.jsAPI adds deep-access hooks for tracing and monitoring
• The experimental after() hook lets you run background tasks (logging, analytics) once the response is sent, improving user experience
• Better hydration error messages make debugging React issues more intuitive

• @next/codemod CLI automates breaking-change migrations—with codemods for async APIs, React 19, and more
• next/form brings client-side navigation to form components for smoother UX
• Support for TypeScript in next.config.ts improves config safety and developer confidence
• Now supports ESLint 9, aligning with the latest linting standards

• Enhanced security for Server Actions, delivering unguessable endpoints and guarding unwanted actions
• Better control over external package bundling and self-hosting tools like automatic image optimization—plus manual Cache-Control headers