Upgrade Next.js Without the Guesswork
React 19 requirement, async request APIs, fetch caching changes — we show you exactly which dependency versions work with Next.js 14 and 15.
No credit card required • 25 free credits • Works with Next.js 12-15
Real Problems From Real Next.js Developers
These quotes are from r/nextjs this week. Sound familiar?
"Upgraded to Next.js 15 and now everything needs React 19 which breaks half our libraries"
"cookies() and headers() are async now?? Every single page and layout needs changes"
"Our auth library dropped Next.js 13 support but we can't upgrade to 15 yet because of other deps"
"Fetch not caching by default in Next 15 broke our entire data layer performance"
"eslint-config-next version mismatch gives cryptic errors and nothing works"
"Tried to upgrade from 13 to 15 directly and now both App Router and Pages Router are broken"
Next.js Upgrades Are More Than Just next@15
The Next.js core upgrade is one step. Your React version, auth, data fetching, and ESLint all need to align.
From Upgrade Anxiety to Upgrade Confidence
Three simple steps to know exactly which versions work together
Run DepFixer Migrate
Run the migrate command and select your target Next.js version. We detect your framework and show available upgrade paths.
Review Migration Plan
See exactly which packages need updates, breaking changes, and React version requirements before committing.
Apply & Install
Confirm the migration and DepFixer updates your package.json. Then run npm install.
Complete Next.js Ecosystem Support
We track version compatibility for the entire Next.js ecosystem
React
UI library (peer dep)
React DOM
DOM rendering
eslint-config-next
ESLint configuration
@next/bundle-analyzer
Bundle analysis
@next/mdx
MDX integration
next-auth
Authentication
@auth/nextjs
Auth.js adapter
next-themes
Theme switching
next-intl
Internationalization
@types/react
TypeScript types
@types/react-dom
TypeScript types
next-mdx-remote
Remote MDX
@vercel/analytics
Vercel Analytics
@next/eslint-plugin-next
ESLint plugin
+ 1.5M+ package versions in our compatibility database
Built for Real Migration Scenarios
Whether you're upgrading one app or coordinating across teams, we've got you covered
Next.js 15 + React 19 Migration
React 19 required
Safely upgrade to Next.js 15 and React 19 together without breaking your ecosystem.
Async API Migration
cookies() / headers()
Handle the async request API changes and ensure all your middleware and page code is compatible.
App Router Adoption
Pages → App Router
Migrate from Pages Router to App Router with confidence in your dependency alignment.
Ship Next.js 15 With Confidence
Know exactly which versions work before you run npm install.
Analyze My Next.js Project FreeNo credit card required • 25 free credits • Results in seconds