# Node UnhandledPromiseRejection Crashes the Job in CI - Handle the Rejection

> Fix Node.js UnhandledPromiseRejection crashes in CI by awaiting or catching the rejecting promise so the process does not exit non-zero on the default throw mode.

Source: https://latchkey.dev/learn/node-js/node-unhandled-promise-rejection-exit-in-ci  
Updated: 2026-06-26

On modern Node the default unhandled rejection mode is throw, so a promise that rejects with no catch terminates the process and fails the CI job.

## Diagnose it: the shell in CI is not your shell

Package scripts run under a different shell, a different PATH, and a non-interactive environment on a runner. Most scripts that fail only in CI are relying on something the login shell gave them locally: a tool on PATH, an environment variable from a dotfile, or a TTY.

```Terminal
# what the script can actually see
npm run env | grep -E "^(PATH|NODE_ENV|CI)=" 

# is the binary on PATH for the script, not just for you?
npm exec -- which <tool> || echo "not resolvable from npm scripts"

# run the exact script with tracing
sh -x -c "$(node -p "require('./package.json').scripts.build")"
```

> A tool installed globally on your machine but only a devDependency in the repo works locally and fails in CI. Call it through `npm exec` or a `node_modules/.bin` path rather than assuming it is on PATH.

## Make failures fail the job

A multi-command script can report success while a middle command failed, which produces the worst kind of CI result: a green build that shipped something broken.

```.github/workflows/ci.yml
# pipefail is NOT set by default in every runner shell
- name: Build
  shell: bash
  run: |
    set -euo pipefail
    npm run build | tee build.log
```

> Without `pipefail`, the exit status of a pipeline is the status of the LAST command, so `failing-command | tee log` reports success. Piping build output to a log file is exactly where this bites.

## FAQ

### What causes Node UnhandledPromiseRejection crashes the job in CI?

There are 2 common causes: a promise without await or catch and a missing await inside an async function. An async call is fired and forgotten; when it rejects there is no handler, so the default throw mode kills the process.

### How do I fix Node UnhandledPromiseRejection crashes the job in CI?

There are 2 fixes depending on which cause you have: await and wrap in try/catch and add a global handler as a backstop. Work through them in order, since the first is the most common.

### What does Node UnhandledPromiseRejection crashes the job in CI actually mean?

A node process prints UnhandledPromiseRejection (or an unhandled rejection stack) and exits non-zero.

### How do I stop Node UnhandledPromiseRejection crashes the job in CI happening again?

Enable the no-floating-promises lint rule, await every promise or attach a catch, and keep the default throw rejection mode so unhandled rejections fail loudly in CI.

---

Latchkey runs CI/CD that repairs its own failures. Agent entry points: https://latchkey.dev/agent.txt, https://latchkey.dev/openapi.json, https://latchkey.dev/llms.txt