Optimizing Memory Usage in Next.js – Reducing Build Pressure and Improving Development Stability

Introduction

Large and feature-rich applications can consume significant memory during development and build processes. Next.js provides several tools and configuration options to help manage and reduce memory usage.

1. Reduce Number of Dependencies

More dependencies mean more memory usage. Use the Bundle Analyzer to identify large or unused packages and remove them to improve performance.

2. Enable webpackMemoryOptimizations

Starting in v15.0.0, you can enable experimental.webpackMemoryOptimizations: true in next.config.js to reduce memory usage during builds. This may slightly increase compilation time but is considered low-risk.

3. Run Build with Memory Debug Mode

From v14.2.0, run:

next build --experimental-debug-memory-usage

This prints memory usage stats and takes heap snapshots when usage nears the limit.

4. Record a Heap Profile

To detect memory leaks, run:

node --heap-prof node_modules/next/dist/bin/next build

Load the resulting .heapprofile file in Chrome DevTools → Memory tab.

5. Analyze Heap Snapshots

Use NODE_OPTIONS=--inspect to expose the inspector agent. You can connect Chrome DevTools to record and analyze memory usage. Send a SIGUSR2 signal to trigger a snapshot during debug mode.

6. Use Webpack Build Worker

From v14.1.0, Webpack runs in a separate worker by default, reducing memory usage. If using a custom Webpack config, enable:

experimental.webpackBuildWorker: true

7. Disable Webpack Cache

Webpack caching increases memory usage. You can disable it with:

config.cache = Object.freeze({ type: 'memory' })

8. Disable TypeScript Static Analysis

Typechecking can consume a lot of memory. To disable during builds:

typescript: {
  ignoreBuildErrors: true,
}

Warning: This may allow type errors into production. Use with caution.

9. Disable Source Maps

Source maps increase memory usage. Disable them with:

productionBrowserSourceMaps: false,
experimental.serverSourceMaps: false,
enablePrerenderSourceMaps: false

10. Update for Edge Runtime Fixes

v14.1.3 fixed memory issues in the Edge runtime. Upgrade to this version or later if you're using Edge.

11. Disable Preloading Entries

Next.js preloads page modules at server start. To reduce initial memory footprint:

experimental.preloadEntriesOnStart: false

Conclusion

By applying these strategies, you can reduce memory usage in your Next.js project, prevent out-of-memory errors, and improve development stability. These optimizations are especially useful for large-scale applications and CI environments.