tsc out of memory (JavaScript heap) - in CI

By Daniel Zoghalchali·Latchkey

The Node process running tsc exhausted V8's heap and aborted, common on large projects or small runners.

What this error means

Type-checking dies with FATAL ERROR: Reached heap limit Allocation failed - JavaScript heap out of memory, often after running a while.

FATAL ERROR: Reached heap limit Allocation failed - JavaScript heap out of memory
 1: 0xb09c10 node::Abort()

Common causes

How to fix it

Raise Node's heap limit

1. Give V8 more old-space via NODE_OPTIONS, kept below the runner's real RAM

export NODE_OPTIONS=--max-old-space-size=4096
npx tsc --noEmit

Shrink the type-check scope

1. Split into project references and build incrementally
2. Run tsc on changed projects only where possible

How to prevent it

• Right-size the runner, split large codebases with project references, and set a sensible --max-old-space-size. Faster managed runners (Latchkey) with more RAM and dependency caching make heavy type-checks finish well within the heap budget.

Frequently asked questions

Related guides

References

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