Matrix Strategy

ELI5 — The Vibe Check

Matrix Strategy is CI/CD's way of testing every combo without writing every combo. Test on Node 18, 20, and 22? On Ubuntu and macOS? Matrix makes a grid and runs ALL combinations in parallel. It's like ordering every pizza topping combination without having to list them all.

Real Talk

Matrix strategy in GitHub Actions generates multiple job runs from a set of variable combinations. Each combination runs as a separate job in parallel. Supports include/exclude rules for fine-grained control and fail-fast behavior to cancel remaining jobs on first failure.

Show Me The Code

jobs:
  test:
    strategy:
      matrix:
        node: [18, 20, 22]
        os: [ubuntu-latest, macos-latest]
        exclude:
          - node: 18
            os: macos-latest
    runs-on: ${{ matrix.os }}
    steps:
      - uses: actions/setup-node@v4
        with:
          node-version: ${{ matrix.node }}

When You'll Hear This

"Our matrix tests across 3 Node versions and 2 OS variants." / "Matrix strategy caught that our code breaks on Node 18 but works on 20."