Enterprise CI/CD Was So Slow Devs Made Coffee. Jenkins to GitHub Actions Fix.

Enterprise e-commerce platform. Jenkins pipelines so slow that developers would start a build and go make coffee. Multiply that by every pull request, every feature branch, every hotfix. The migration from legacy Jenkins monolith pipelines to parallelized GitHub Actions - with caching, matrix builds, and actual feedback loops. Builds that used to take an hour now run in minutes. Enterprise environment, enterprise constraints — and fixes that actually shipped. The Jenkins setup was textbook legacy pain: everything sequential, no build caching so every run was a full rebuild, shared runners that queued 20 minutes before a build even started, and flaky tests nobody dared touch. The only fix was to re-run and hope for green. Before writing a line of new config, I mapped all 47 active pipelines. No documentation existed - I mapped the ones actually running. Some hadn't been touched in three years but were still running daily. The new architecture was modular. Shared workflows reusable across every repo in the organization. Matrix builds running tests in parallel across multiple Node versions. Build analytics tracking pipeline performance per pull request so you could see if your…