Next.js 15: The Good, The Bad, and What Nobody Tells You
🎯 Why I Upgraded
Next.js 15 promised better performance, improved App Router, and a bunch of new features. My app was on Next.js 13, and I thought it was time to upgrade. Two weeks later, I'm still fixing issues.
✅ The Good
1. Performance Improvements
The performance gains are real. I saw about 15-20% improvement in page load times, especially with the new caching strategies.
2. Better TypeScript Support
TypeScript integration is much better. Fewer type errors, better autocomplete, and improved type inference.
3. Improved Developer Experience
The dev server is faster, hot reload works better, and the error messages are more helpful.
❌ The Bad
1. Breaking Changes Everywhere
The migration guide says "minimal breaking changes." That's a lie. I had to refactor:
- All my API routes (new structure)
- Middleware (completely different API)
- Server components (new patterns)
- Client components (new boundaries)
2. Documentation Gaps
The documentation doesn't cover edge cases. I spent days debugging issues that weren't documented anywhere.
3. Third-Party Library Compatibility
Many libraries haven't caught up. I had to wait for updates or find alternatives for several dependencies.
⚠️ What Nobody Tells You
The App Router is still not production-ready for complex apps. Simple blogs? Fine. Complex dashboards? Prepare for pain.
Server Actions are great, but they have limitations that aren't obvious until you hit them.
💡 Should You Upgrade?
Yes, if:
- You're starting a new project
- You have time to deal with breaking changes
- You need the performance improvements
No, if:
- You're on a tight deadline
- Your app is complex and working fine
- You rely on many third-party libraries
🎯 Conclusion
Next.js 15 is good, but it's not the revolutionary upgrade the marketing suggests. The improvements are real, but so are the migration costs. Plan accordingly.