Speed Up CI: Practical GitHub Actions Cache Monorepo Strategies for JavaScript Monorepos
Surprising fact: properly designed caching in a JavaScript monorepo can cut CI run time by more than half — our sample monorepo went from 32 minutes to 9 minutes after switching to a hybrid caching strategy. If your GitHub Actions pipelines feel slow or expensive, a few key cache design changes will give you the best ROI. Why caching matters in CI for monorepos Monorepos compound the usual Node.js install/build costs: many packages, duplicated dependencies, and cross-package build effects. Common pain points: Long dependency installs on every CI run Frequent cache misses due to poor key design Race conditions when multiple matrix jobs try to populate the same cache Concrete impact: in our case study (120 packages, many shared deps) switching from naive node_modules caching to a pnpm + hybrid cache model reduced CI minutes by ~72% and large .html" style="color:#0066cc;text-decoration:none;">large -javascript.html" title="How to Migrate a L...