Angular "JavaScript heap out of memory" during ng build in CI

A large Angular production build (AOT plus optimization) can allocate more memory than Node's default old-space limit, and V8 aborts with a heap out-of-memory fatal error. Raising the Node heap via NODE_OPTIONS usually fixes it.

What this error means

ng build --configuration production dies with "FATAL ERROR: Reached heap limit Allocation failed - JavaScript heap out of memory" and a V8 stack trace.

<--- Last few GCs --->
FATAL ERROR: Reached heap limit Allocation failed - JavaScript heap out of memory

Common causes

A large build exceeds the default Node heap

AOT compilation and optimization of a big app can need more than Node's default old-space size, so V8 runs out of heap.

A runner with limited memory

A smaller runner has less RAM, so the same build that passes on a larger machine hits the heap ceiling in CI.

How to fix it

Raise the Node heap with NODE_OPTIONS

Set --max-old-space-size high enough for the build, within the runner's available memory.

env:
  NODE_OPTIONS: --max-old-space-size=4096
run: npx ng build --configuration production

Reduce build memory pressure

Split large lazy modules and use a runner with more RAM if the heap flag alone is not enough.

How to prevent it

• Set NODE_OPTIONS max-old-space-size for large Angular builds in CI.
• Keep the value below the runner's physical memory.
• Use a runner sized for your build, and lazy load to shrink it.

Related guides