How software is built: the lifecycle

Software is built in a repeating cycle, often called the software development lifecycle, or SDLC. Someone spots a need. The team designs a solution.

Engineers build it in small pieces, and other engineers review the code. Automated tests check it, and sometimes QA (quality assurance) testers check it by hand too. It is released to users, and the team then runs and improves it.

In practice these steps overlap and repeat every week or two. Each non-coding role plugs in at specific points. PMs shape the need and measure the result.

Writers document the feature before or at release. Advocates teach it once it is live and bring back feedback. Knowing the whole cycle tells you when your input is cheap and when it is too late.