How to Cache the Build Output Between Jobs in GitHub Actions

Caching the compiled output keyed on a source hash lets downstream jobs restore it instead of building from scratch.

Cache the build directory with a key derived from the source files. The build job populates it once, and test or lint jobs restore it when the source is unchanged.

Steps

• Key the cache on hashFiles of source plus the lockfile.
• Build once, then restore the same key in dependent jobs.
• Use a job artifact instead when the consumer always needs the latest build.

Workflow

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/cache@v4
        with:
          path: dist
          key: build-${{ hashFiles('src/**', 'package-lock.json') }}
      - run: npm ci && npm run build

Gotchas

• If any consumer must always get the freshest build, use upload/download-artifact, not a cache.
• A cache key that omits a build input restores stale output; include every file that affects the build.

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