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

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.

vite

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.

Terminal

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

Use build.rollupOptions.output.manualChunks to break up large vendor chunks.
Lazy-load routes/components so fewer modules render at once.
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.