NextJS Build Times Destroying Your Productivity? Here's How to Fix It

I was debugging a build that was taking 45+ minutes on a good day, sometimes longer. This was during our Black Friday deploy and everything went to shit. The build that used to finish in maybe 3-4 minutes was now eating up our entire CI budget and killing deployments.

Here's the thing about NextJS build performance - it sneaks up on you. You add a few dependencies, maybe some custom webpack config, a couple of dynamic imports, and suddenly your builds are crawling. But the real killer isn't usually what you think it is.

The Real Culprits Behind Slow Builds

TypeScript compilation eating memory like a starved beast. I've seen builds where TypeScript was consuming 6GB+ of RAM trying to type-check everything at once. The default TypeScript config in NextJS is way too aggressive for large codebases.

Dependency resolution hell. One project I worked on was resolving packages 50+ times during build. Same package, same version, but webpack couldn't figure its shit out. This adds minutes to every build and is a common NextJS performance bottleneck.

CSS-in-JS libraries doing way too much work. Looking at you, @emotion/react. These libraries are convenient until they start parsing and generating CSS for every single component during build time.

Static analysis tools running in the wrong order. ESLint + TypeScript + Prettier all fighting each other during build instead of working together. I've seen this add 10+ minutes to builds when not properly configured.

Source map generation for files that don't need it. NextJS generates source maps for everything by default, including vendor chunks. This is insane for production builds and a major performance killer.

The worst part? Most of the "solutions" you'll find online are either outdated or written by people who haven't actually dealt with large NextJS apps in production. Half the advice breaks in Next 14, and the other half only works if you're building a todo app. The official performance docs are better but still miss the production gotchas.

What Actually Breaks in Real Projects

Memory exhaustion during large imports. Node runs out of heap space when processing large dependency trees. The default Node heap limit is usually too small for modern NextJS apps with heavy dependencies.

GitHub Actions timing out after 6 hours. Yeah, builds can get that slow. I've seen it happen when webpack optimization goes wrong and starts building circular dependencies.

Development server taking 5+ minutes to start. This isn't just a build issue - it kills developer productivity when you're waiting half your standup for the dev server to boot. NextJS dev server optimization is critical for team velocity.

Hot reloading breaking completely. Fast refresh stops working when your build config gets too complex, forcing full page reloads for every change. This is usually a sign your webpack configuration is fucked.

The solutions I'm about to show you actually work because I've used them to fix real production builds that were completely fucked.

These fixes are ranked by what actually works in production. I've wasted way too many hours on solutions that sound good in theory but break everything in practice.

Fix #1: Stop TypeScript From Destroying Your Build

TypeScript is probably your biggest performance killer. The default config is way too aggressive for large projects.

First, bump your Node heap limit:

export NODE_OPTIONS=\"--max_old_space_size=8192\"

Next, fix your TypeScript config. Add this to your tsconfig.json:

{
  \"compilerOptions\": {
    \"incremental\": true,
    \"tsBuildInfoFile\": \".next/cache/tsconfig.tsbuildinfo\"
  },
  \"ts-node\": {
    \"swc\": true
  }
}

This enables incremental compilation and uses SWC instead of the slower TypeScript compiler. Cut our build times from like 20 minutes down to maybe 6-7 minutes. More details on TypeScript performance optimization.

Fix #2: Make Webpack Less Stupid

NextJS webpack config is optimized for small projects, not real applications. The default webpack configuration needs tweaking for production workloads.

// next.config.js
module.exports = {
  webpack: (config, { dev, isServer }) => {
    // Stop webpack from being an idiot about caching
    config.cache = {
      type: 'filesystem',
      buildDependencies: {
        config: [__filename]
      }
    }
    
    // Split chunks properly - this shit will murder build times otherwise
    if (!dev && !isServer) {
      config.optimization.splitChunks.chunks = 'all'
      config.optimization.splitChunks.cacheGroups = {
        framework: {
          chunks: 'all',
          name: 'framework',
          test: /(?<!node_modules.*)[\\/]node_modules[\\/](react|react-dom|scheduler|prop-types|use-subscription)[\\/]/,
          priority: 40,
          enforce: true
        }
      }
    }

    return config
  }
}

This enables filesystem caching and fixes the chunk splitting that NextJS fucks up by default. Learn more about webpack optimization.

Fix #3: Deal With CSS-in-JS Performance

CSS-in-JS libraries are convenient until they destroy your build times. Here's what actually works for styled-components performance and Emotion optimization:

For styled-components: Enable the SWC plugin:

// next.config.js
const nextConfig = {
  compiler: {
    styledComponents: true
  }
}

For Emotion: Switch to the SWC version:

npm uninstall @emotion/babel-plugin
npm install @emotion/react @emotion/styled

Then update your config:

// next.config.js
const nextConfig = {
  compiler: {
    emotion: true
  }
}

This cut CSS processing time by more than half on projects I've worked on. The SWC compiler is much faster than Babel for CSS-in-JS processing.

Fix #4: Fix Your Import Strategy

Dynamic imports are great until you have hundreds of them. Here's what I learned the hard way about code splitting optimization:

Batch your dynamic imports:

// Instead of this (slow as hell)
const ComponentA = dynamic(() => import('./ComponentA'))
const ComponentB = dynamic(() => import('./ComponentB'))
const ComponentC = dynamic(() => import('./ComponentC'))

// Do this (much faster)
const DynamicComponents = dynamic(() => 
  Promise.all([
    import('./ComponentA'),
    import('./ComponentB'), 
    import('./ComponentC')
  ]).then(([A, B, C]) => ({ A: A.default, B: B.default, C: C.default }))
)

Pre-bundle heavy dependencies:

// next.config.js
module.exports = {
  experimental: {
    optimizePackageImports: ['lodash', 'date-fns', 'react-icons']
  }
}

This tells NextJS to pre-bundle these packages instead of processing them every time.

Fix #5: Stop Generating Useless Source Maps

Source maps are great for debugging but they're killing your production builds:

// next.config.js
module.exports = {
  productionBrowserSourceMaps: false, // Disable this shit in production
  webpack: (config, { dev }) => {
    if (!dev) {
      config.devtool = false // Nuclear option - no source maps at all
    }
    return config
  }
}

For projects where you need some source mapping:

// Only for your code, not vendor code
config.devtool = 'hidden-source-map'

Fix #6: Make CI Actually Usable

If you're using GitHub Actions, the default setup is trash for NextJS builds:

## .github/workflows/build.yml
- name: Setup Node.js
  uses: actions/setup-node@v3
  with:
    node-version: '18'
    cache: 'npm'

- name: Configure build environment
  run: |
    export NODE_OPTIONS=\"--max_old_space_size=8192\"
    export NEXT_TELEMETRY_DISABLED=1

- name: Install dependencies
  run: npm ci --prefer-offline --no-audit

- name: Build
  run: |
    npm run build
  env:
    NODE_OPTIONS: --max_old_space_size=8192

The key is disabling telemetry (saves a few seconds) and using npm ci with offline preference.

When Nothing Works: Nuclear Options

Sometimes your build is just fundamentally broken. Here's when to give up and try something else:

If you're on Next 12 or older: Upgrade. Seriously. The build improvements in Next 13+ are worth the migration pain.

If you're using too many dynamic imports: Consider switching to static imports with code splitting at the page level instead.

If your bundle size is over 10MB: You probably need to rethink your architecture. Consider micro-frontends or splitting your app into multiple Next apps.

If builds still take 30+ minutes after all this: Your codebase might be too big for NextJS. Consider Vite or switching to a different build tool entirely.

I've seen projects where the answer was literally "start over with a different framework" because the technical debt was too deep to fix economically.