Why it matters
It's the vocabulary of every scoping conversation: "front-end change" usually means fast and visual, "back-end change" means logic and data, slower and riskier to rush. Knowing which side a request touches keeps estimates and expectations realistic.
How it works
The front end runs in the visitor's browser (HTML, CSS, JavaScript); the back end runs on servers, exposing data and actions through APIs the front end calls. Marketing sites can be nearly all front end; applications carry real weight on both sides.
What to do about it
When briefing work, describe outcomes and let the builders locate the change, but ask which side it lands on. The answer predicts cost, risk and timeline better than the feature's apparent size.
