Welcome to the Capstone, the final stop in the Software Engineering Fundamentals course. Every module so far has ended with its own guided project. This one is different: it pulls all four modules together into a single, real feature for Ledgerly — prorated mid-cycle subscription plan upgrades — built completely from scratch.

You’ll frame the work with user stories and a methodology choice from Engineering Foundations, design a composed ProrationCalculator with a deliberately chosen pattern from Design, Architecture & OOP, implement and thoroughly test it using the practices from Writing Quality, Tested Code, and close with the CI and security awareness from Delivery & Operations. A final report ties every stage back to the exact lesson that taught it.

Every number in this capstone comes from real, executed code. Start the lesson to build Ledgerly’s last feature end to end.