Coupling
ELI5 — The Vibe Check
Coupling is how much two pieces of code depend on each other. Tight coupling means changing one breaks the other — like Siamese twins. Loose coupling means they barely know each other — like coworkers who communicate through Slack. Loose coupling is almost always better.
Real Talk
Coupling measures the degree of interdependence between software modules. Tight coupling (high coupling) makes modules difficult to change, test, or reuse independently. Loose coupling is achieved through interfaces, dependency injection, and event-driven communication.
When You'll Hear This
"These two services are too tightly coupled — they deploy together or not at all." / "Reduce coupling by introducing an interface between them."
Related Terms
Cohesion
Cohesion is how well the things inside a module belong together. High cohesion means all the stuff in a class is related — like a toolbox full of tools.
Dependency Injection
Instead of your UserService creating its own DatabaseConnection (tight coupling), you pass the database in from outside: new UserService(db).
Dependency Inversion
Dependency Inversion says high-level code shouldn't depend on low-level code — both should depend on abstractions.
Separation of Concerns
Separation of Concerns means different parts of your code should handle different concerns and not step on each other's toes.