Welcome to Delivery & Operations, the fourth module of the Software Engineering Fundamentals course. Clean, tested code from Module 3 still needs a safe path into production. You’ll start with a short, conceptual version control overview — the working-directory/staging/commit mental model and why teams like Ledgerly’s use one branch per feature — with a pointer to this site’s dedicated Git & GitHub course for full depth.

From there, you’ll build a real CI/CD pipeline for Ledgerly that lints, runs Module 3’s test suite, and gates a deploy, and see exactly what separates continuous delivery from continuous deployment. You’ll then defend Ledgerly’s code directly: fixing a real SQL injection vulnerability against a live in-memory database, and replacing a hardcoded payment-gateway API key with one read from the environment. A guided project closes the module by shipping one real feature through all three: a clean commit, a working pipeline, and a verified security fix.

Every pipeline and every fix in this module runs for real. Start with Lesson 1, where you’ll meet the mental model behind every commit Ledgerly’s team makes.