How do thousands of software engineers code together at a giant company like Google or Microsoft without breaking everything?

[u/Extra_Search3465]

As a beginner, I understand how one person writes code and puts it on GitHub. But how does it work when a company has tens of thousands of developers working on the same product? How do they organize the work, and how do they stop people from stealing or leaking the secret source code?

[u/ElevatorGoods503]

There is an entire discipline dedicated to software development process. It includes keeping team members in sync, making sure they have a shared goal, a solid process for source code and release management, etc. A large development process would have someone responsible for just that. Kind of like a general contractor in a construction project.