Slashing CI/CD Runtime by 50% with GitHub Actions Optimization

The Problem

Our GitHub Actions pipeline was taking 40+ minutes. Engineers were losing focus waiting for CI results.

Optimization Techniques

1. Aggressive Dependency Caching

- uses: actions/cache@v4
  with:
    path: |
      ~/.npm
      node_modules
    key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}
    restore-keys: |
      ${{ runner.os }}-node-

2. Parallel Job Matrix

Split tests across 4 workers:

strategy:
  matrix:
    shard: [1, 2, 3, 4]
steps:
  - run: npm test -- --shard=${{ matrix.shard }}/4

3. Skip Redundant Steps

Use `paths` filters to skip Docker builds when only docs change:

on:
  push:
    paths:
      - 'src/**'
      - 'Dockerfile'

Results