How do I run tests in parallel with GitHub Actions matrix?

Question

Suite takes 40 min. Want to shard across 4 runners. What does the workflow look like?

Priya Gopal · Accepted Answer

Use a build matrix to fan the same job out across versions, browsers or shards. GitHub Actions runs each combination as a parallel job on its own runner.

```yaml
jobs:
  test:
    runs-on: ubuntu-latest
    strategy:
      fail-fast: false
      matrix:
        shard: [1, 2, 3, 4]
    steps:
      - uses: actions/checkout@v4
      - run: npm ci
      - run: npx playwright test --shard=${{ matrix.shard }}/4
```

Two things matter in practice. Set `fail-fast: false` or the first failing shard cancels the rest and you lose the full failure picture. And upload per-shard reports as artifacts with a shard-suffixed name, then merge them in a final job (`playwright merge-reports`) so you get one HTML report instead of four. Sharding four ways typically cuts a 20-minute suite to 5–6 minutes; beyond ~8 shards, runner startup overhead starts eating the gain.

jobs:
  test:
    strategy:
      fail-fast: false
      matrix:
        shard: [1, 2, 3, 4]
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with: { node-version: 20, cache: 'npm' }
      - run: npm ci
      - run: npx playwright test --shard=${{ matrix.shard }}/4

How do I run tests in parallel with GitHub Actions matrix?

1 answer