Vite "JavaScript heap out of memory" on Large App Builds in CI

By Kaveh Alemi·Latchkey

A large vite build runs Rollup over thousands of modules, and the Node process can exhaust V8's heap on a constrained runner. It aborts with the same OOM as any other Node build.

What this error means

vite build dies with FATAL ERROR: Reached heap limit Allocation failed - JavaScript heap out of memory, usually late in the production Rollup pass, on a runner with less RAM than your laptop.

transforming...
✓ 3120 modules transformed.
rendering chunks...
<--- Last few GCs --->
FATAL ERROR: Reached heap limit Allocation failed - JavaScript heap out of memory

Common causes

Heap default too low for a big Rollup pass

Many modules, large source maps, and heavy chunking inflate peak memory beyond V8's default old-space cap.

Constrained CI runner

A small runner or container memory cap gives Node less RAM than the build peak, so it OOMs where a bigger machine would not.

How to fix it

Raise Node's heap and trim source maps

Give V8 more old-space and reduce source-map cost for the build.

export NODE_OPTIONS=--max-old-space-size=4096
vite build
# vite.config.ts: build: { sourcemap: false } // or 'hidden' in CI

Split chunks and lazy-load routes

1. Use build.rollupOptions.output.manualChunks to break up large vendor chunks.
2. Lazy-load routes/components so fewer modules render at once.
3. Run the build on a larger runner for genuinely large apps.

How to prevent it

• Set a sensible --max-old-space-size for the build job.
• Trim source maps and split chunks to lower peak memory.
• Faster managed runners such as Latchkey offer more RAM plus dependency caching so large Vite builds complete under the heap ceiling and transient OOMs are auto-retried.

Frequently asked questions

Related guides

References

• Node.js documentation
• npm CLI documentation
• GitHub Actions documentation