A near-identical copy of the live app used to try updates before they reach customers.
Staging is a separate copy of your app with settings close to the real environment but with test data and payments in test mode. It is where you try new features and confirm everything works before the update reaches customers in production.
Testing updates directly on the live app can break orders, message real customers or corrupt data. Staging gives you a safe place to make mistakes, which matters especially with AI-generated code that needs verification before you rely on it. Practical tip: use only test payment keys in staging and never copy real customer data into it without masking personal information. Make try it in staging, then deploy a fixed habit.