If you started your QA career testing a monolithic application, you already have a foundation. But that foundation can quietly work against you in a microservice system — because the rules have changed, and most junior QA engineers don't realize it until something breaks in a way they can't explain. This article will help you understand how microservice systems are built, why they behave differently, and what you need to start thinking about as a QA engineer working in one. What Even Is a Microservice Architecture? In a traditional monolithic application, everything lives in one place. The user interface, the business logic, the database — all bundled together. When you test a login feature, you're testing one system. Microservice architecture breaks that single system into smaller, independently running services.…