Next.js 15 brings major enhancements for developers, including async APIs for handling request-specific data, refined caching defaults, compatibility with React 19, and the stable release of Turbopack for faster builds. New features like the <Form> component, ESLint 9 support, and advanced security measures further improve development speed and application stability. Enhanced debugging for hydration errors, a static route indicator, and support for TypeScript in next.config.ts add additional flexibility. These upgrades make it easier to build high-performance, scalable web apps.