Unit tests focus on testing individual units of code, typically functions or methods, in isolation from the rest of the system. The goal is to ensure that each unit behaves as expected, usually with mock data or dependencies. Unit tests are fast, isolated, and help identify bugs at an early stage in development.
Integration tests, on the other hand, check how different modules or components of the system work together. They test the interaction between various parts of the application, such as databases, APIs, or external services, to ensure that they function correctly when integrated. Integration tests are generally slower and more complex than unit tests but are crucial for verifying the overall system behavior.